Troubleshooting
Overview
This chapter offers some suggestions to solve problems you might encounter. The potential problems are divided into the following categories.
Power, Hardware Connections, and LED
The Zyxel Device does not turn on. The LED is not on.
1 Make sure you are using the power adapter included with the Zyxel Device or a PoE power injector/switch. If your Zyxel Device uses a type C power adapter, and you want to use your own type C adapter, ensure that the power supply is at least 45W.
2 Make sure the power adapter or PoE power injector/switch is connected to the Zyxel Device and plugged in to an appropriate power source. Make sure the power source is turned on.
3 Disconnect and re-connect the power adapter or PoE power injector/switch. Check that you are using the correct PoE port on the PoE power injector/switch to supply power to the Zyxel Device.
4 Inspect your cables for damage. Contact the vendor to replace any damaged cables.
5 If none of these steps work, you may have faulty hardware and should contact your Zyxel Device vendor.
The LED does not behave as expected.
1 Make sure you understand the normal behavior of the LED. See Zyxel Device LED.
2 Check the hardware connections. See the Quick Start Guide.
3 Inspect your cables for damage. Contact the vendor to replace any damaged cables.
4 Disconnect and re-connect the power adapter or PoE power injector to the Zyxel Device.
5 If the problem continues, contact the vendor.
Zyxel Device Management, Access, and Login
I forgot the IP address for the Zyxel Device.
1 The default in-band IP address in standalone mode is https://DHCP-assigned IP (when connecting to a DHCP server) or 192.168.1.2.
2 If you changed the IP address and have forgotten it, you have to reset the Zyxel Device to its factory defaults. See Resetting the Zyxel Device.
3 If your Zyxel Device is a DHCP client, you can find your IP address from the DHCP server. This information is only available from the DHCP server which allocates IP addresses on your network. Find this information directly from the DHCP server or contact your system administrator for more information.
4 If the NCC has managed the Zyxel Device, you can also check the NCC's Site-wide > Devices > Access points screen for the Zyxel Device's current LAN IP address.
I cannot see or access the Login screen in the Web Configurator.
1 Make sure you are using the correct IP address.
• The default IP address (in standalone mode) is 192.168.1.2.
• If you changed the IP address, use the new IP address.
• If you changed the IP address and have forgotten it, see the troubleshooting suggestions for I forgot the IP address for the Zyxel Device.
2 Check the hardware connections, and make sure the LED is behaving as expected. See the Quick Start Guide and Zyxel Device LED.
3 Make sure your Internet browser does not block pop-up windows and has JavaScripts and Java enabled.
4 Make sure your computer is in the same subnet as the Zyxel Device. (If you know that there are routers between your computer and the Zyxel Device, skip this step.)
• If there is a DHCP server on your network, make sure your computer is using a dynamic IP address. Check the DHCP IP address assigned to your Zyxel Device on the connected router.
• If there is no DHCP server on your network, make sure your computer’s IP address is in the same subnet as the Zyxel Device.
5 Reset the Zyxel Device to its factory defaults, and try to access the Zyxel Device with the default IP address. See Resetting the Zyxel Device.
6 If the problem continues, contact the network administrator or vendor, or try one of the advanced suggestions.
Advanced Suggestions
• Try to access the Zyxel Device using another service, such as SSH. If you can access the Zyxel Device, check the remote management settings to find out why the Zyxel Device does not respond to HTTP.
• If your computer is connected wirelessly, use a computer that is connected to a LAN/ETHERNET port.
I forgot the Web Configurator password.
1 The default password is unique to each Zyxel Device and shown on the label. If your Zyxel Device does not have a password on the label, use “1234”. If the Zyxel Device is connected to the NCC and registered, check the NCC for the password.
2 If this does not work, you have to reset the Zyxel Device to its factory defaults. See Resetting the Zyxel Device.
I can see the Login screen, but I cannot log into the Zyxel Device.
1 Clear your browser’s cache.
2 Check the Zyxel Device’s management mode.
• The default password is unique to each Zyxel Device and shown on the label. If your Zyxel Device does not have a password on the label, use “1234”. If you have changed the username and password, use the ones you configured to log in.
• If the Zyxel Device is in cloud managed mode, use the Nebula Local credentials Password to log into the cloud managed mode local GUI. The Local credentials Password can be found in Site-wide > Configure > Site settings > Device configuration: Local credentials: Password in the NCC portal.
3 Depending on your Zyxel Device’s management mode, make sure you have entered the correct user name and password. These fields are case-sensitive, so check if [Caps Lock] is on or off.
*Steps 1 and 2 are applicable if you get an “Invalid password” error message when using some functions in the ZON utility. See Zyxel One Network (ZON) Utility for more information.
4 Disconnect and re-connect the power adapter or PoE power injector to restart the Zyxel Device.
5 If this does not work, you have to reset the Zyxel Device to its factory defaults. See Resetting the Zyxel Device.
I cannot use FTP to upload or download the configuration file.
Ensure you have enabled FTP in the Configuration > System > FTP screen.
I cannot upload the firmware uploaded using FTP.
The Web Configurator is the recommended method for uploading firmware in standalone mode. For managed Zyxel Devices, using the NCC is recommended. You only need to use FTP if you need to recover the firmware. See the CLI Reference Guide for how to determine if you need to recover the firmware and how to recover it.
NCC is managing the Zyxel Device, but the NCC cannot access the Zyxel Device.
Connect to the Zyxel Device directly and log into the Web Configurator with the credentials configured in NCC.
I cannot register the Zyxel Device in NCC because it’s already registered by the previous owner.
• If the previous owner has registered the Zyxel Device in NCC and has enabled the NCC Override device ownership feature in the Organization-wide > Organization-wide manage > Organization settings screen, use the Nebula Mobile app to scan the NCC QR code on the back label of the Zyxel Device to register with NCC.
• If the previous owner has registered it in NCC and has locked the Zyxel Device with the NCC Override device ownership feature in the Organization-wide > Organization-wide manage > Organization settings screen, inform the previous owner to unregister the Zyxel Device or contact Zyxel technical support.
The Zyxel Device is already registered with NCC, but it is still in standalone mode; it cannot connect to the NCC.
1 Check the Zyxel Device LED and make sure the Zyxel Device is on and ready for use.
2 Check your network’s firewall/security settings. Make sure the following ports are allowed:
• TCP: 443, 4335, and 6667
• UDP: 123 is allowed.
3 Make sure your Zyxel Device has obtained an IP address and can access the Internet. Check the Cloud Control Status on the Dashboard screen for your Internet connection.
4 Check your network’s VLAN settings (see VLAN). You may have to change the Management VLAN settings of the Zyxel Device to allow it to connect to the Internet and access the NCC.
*Changing the management VLAN and IP address settings on the Zyxel Device also pushes these changes to the NCC. Do this only if your device cannot otherwise connect to the NCC.
5 Make sure your Zyxel Device does not have to go through network authentication such as a captive portal. If your network uses a captive portal, the network administrator may have to create a new VLAN without this requirement. Change your Zyxel Device’s management VLAN settings as necessary.
6 Make sure your DNS server can resolve d.nebula.zyxel.com. Open the Command Prompt on your computer, enter nslookup d.nebula.zyxel.com, see if the DNS server can return the resolved IP address. If not, you can try set your gateway to use the Google Public DNS server 8.8.8.8. Or, set the DNS server address in the Zyxel Device Web Configurator. Go to Configuration > Network > IP Setting, select Use Fixed IP Address. Set the DNS Server IP Address: to 8.8.8.8. Click Apply.
Some features I set using the NCC do not work as expected.
1 Make sure your Zyxel Device can access the Internet.
2 Make sure the NCC can access the Zyxel Device. Check your network’s firewall/security settings. Make sure the following ports are allowed:
• TCP: 443, 4335, and 6667
• UDP: 123
3 After changing your Zyxel Device settings using the NCC, wait 1-2 minutes for the changes to take effect.
I can only see newer logs. Older logs are missing.
When a log reaches the maximum number of log messages (see Zyxel Device Product Feature Comparison), new log messages automatically overwrite the oldest log messages.
The commands in my configuration file or shell script are not working properly.
• In a configuration file or shell script, use “#” or “!” as the first character of a command line to have the Zyxel Device treat the line as a comment.
• Your configuration files or shell scripts can use “exit” or a command line consisting of a single “!” to have the Zyxel Device exit sub command mode.
• Include write commands in your scripts. Otherwise the changes will be lost when the Zyxel Device restarts. You could use multiple write commands in a long script.
*“exit” or “!'” must follow sub commands if it is to make the Zyxel Device exit sub command mode.
My Zyxel Device’s CPU usage is too high.
The Zyxel Device may receive too many HTTPS connection requests. Do the following to reduce the number of HTTPS connection requests:
Go to Configuration > Object > User > Setting and select Limit the number of simultaneous logons for administration account. Set a number in Maximum number per administration account to limit the number of simultaneous logins for each admin.
How do I set up multiple Access Points (APs)?
Avoid positioning APs in direct line of sight of each other, as this can cause interference and reduce the overall performance of your WiFi network.
In case, it may be necessary to position APs in direct line of sight of each other, you can:
• Adjust the transmit power of each AP in the Configuration > Wireless > AP Management screen, so that they are not using too much power and overlapping too much with each other.
• Configure the APs to operate on non-overlapping channels, such as channels 1, 6, and 11 in the 2.4 GHz band, 5 GHz band or 6 GHz band's channels or enabling DCS to let APs scan the best channel to use. This can help to minimize co-channel interference between the APs.
I only want certain users to access specific parts of my network.
See Restrict Users’ Access to Specific Parts of Your Network for more information on how to allow certain users to access only specific parts of your network.
I only want admins to use HTTPS or SSH to access the Zyxel Device.
See Access to the Zyxel Device for more information on how to configure access to the Zyxel Device.
Internet Access
Clients cannot access the Internet through the Zyxel Device.
1 Check the Zyxel Device’s hardware connections, and make sure the LEDs are behaving as expected (refer to Zyxel Device LED). See the Quick Start Guide and Overview.
2 Make sure the Zyxel Device is connected to a broadband modem or router with Internet access and your computer is set to obtain an dynamic IP address.
3 If clients are trying to access the Internet wirelessly, make sure the WiFi settings on the WiFi clients are the same as the settings on the Zyxel Device.
4 Make sure the Zyxel Device has the same VLAN settings configured as the gateway connected to the Zyxel Device. Traffic tagged with a specific VLAN ID tag can only go to the WiFi clients of the WiFi network that uses the same VLAN ID. If you select Tagged (As Native VLAN) in the Configuration > Network > VLAN screen, traffic going out from the Zyxel Device Ethernet port will be tagged with the Management VLAN ID you set. Devices connected to the Zyxel Device need to have the same VLAN ID configured to receive traffic from the Zyxel Device .
5 Disconnect all the cables from your Zyxel Device, and follow the directions in the Quick Start Guide again.
6 Reboot the client and reconnect to the Zyxel Device
7 If the problem continues, contact your ISP.
The Internet connection is slow or intermittent.
1 There might be a lot of traffic on the network. Look at the LEDs, and check Zyxel Device LED. If the Zyxel Device is sending or receiving a lot of information, try closing some programs that use the Internet, especially peer-to-peer applications.
2 Check the signal strength using the NCC or the Zyxel DeviceWeb Configurator, or the client device itself. If the signal is weak, try moving the client closer to the Zyxel Device (if possible), and look around to see if there are any devices that might be interfering with the wireless network (microwaves, other wireless networks, and so on).
3 Reboot the Zyxel Device using the Web Configurator/CLI or the NCC.
4 Check the settings for QoS. If it is disabled, activate it. When enabled, raise or lower the priority for some applications.
5 If the problem continues, contact the network administrator or vendor.
WiFi Network
I cannot connect to the Zyxel Device WiFi network.
1 Check the Zyxel Device LED status to make sure the Zyxel Device WiFi is on.
2 Make sure your WiFi client is within transmission range of the Zyxel Device.
3 Make sure you enter the correct SSID, password (Pre-Shared Key). They are case-sensitive. See the Zyxel Device back label for the default SSID and password.
4 Make sure your WiFi client is using the same WiFi security type (none, Enhanced-open, WEP, WPA, WPA2, WPA3) as the Zyxel Device. If you have previously changed the security settings, remove the SSID profile on the client device. Reconnect again using the correct SSID, password and security type.
5 Make sure the DHCP server is working properly. For example, the client may receive a private IPv4 address such as 192.168.1.x where x is a number for 2 to 254. If the client gets an address like 169.x.x.x, it means the client didn’t get a valid IP address from the DHCP server.
6 Make sure the DNS server is working properly. If you can ping an IP address, but cannot ping its related URL, then it means there is a DNS server connection issue. For example, if you can ping 8.8.8.8 successfully but fail to ping google.com, there may be a DNS resolution issue.
7 Make sure the WiFi adapter on your WiFi client is working properly.
8 Make sure the wireless adapter on your WiFi client is IEEE 802.11 compatible and supports the same WiFi standard as the Zyxel Device’s active radio. For example, 6 GHz WiFi networks are only available for WiFi clients that support WiFi 6E or higher standards.
The WiFi connection is slow or intermittent.
The following factors may cause interference:
• Obstacles: walls, ceilings, furniture, and so on.
• Building Materials: metal doors, aluminum studs.
• Electrical devices: microwaves, monitors, electric motors, cordless phones, and other wireless devices.
To optimize the speed and quality of your WiFi connection, you can:
• Move your WiFi device closer to the Zyxel Device if the signal strength is low.
• Reduce wireless interference that may be caused by other wireless networks or surrounding wireless electronics such as cordless phones.
• To ensure the connected WiFi clients receive strong WiFi signal, adjust the minimum signal strength between the Zyxel Device and its WiFi clients by going to the Configuration > Object > AP Profile > Radio screen and selecting Enable Signal Threshold. To apply the settings to your Zyxel Device, go to the Configuration > AP Management > AP Group screenand select the Profile Name you just created.
• Place the Zyxel Device where there are minimum obstacles (such as walls and ceilings) between the Zyxel Device and the wireless client. Avoid placing the Zyxel Device inside any type of box that might block WiFi signals.
Bandwidth restriction controls the amount of network traffic that WiFi clients can consume. This prevents the WiFi clients from downloading too many movies and slowing down other devices on the network. See Limit Network Bandwidth for Each WiFi Client for more information on how to restrict network bandwidth for each WiFi client.
Unauthorized users have accessed my wireless LAN.
• WEP is extremely insecure. It is recommended that you use the strongest security mechanism that all the WiFi devices in your network support. WPA2, WPA2-Mix or WPA3 are recommended. See Limit Network Bandwidth for Each WiFi Client for how to change security settings for a WiFi network.
• Rogue AP is an unauthorized access point in the network that poses a security threat. See Set Up Rogue AP Detection for how to set up rogue AP detection.
• A MAC filter list blocks or allows a list of clients based on their MAC addresses, ensuring only authorized clients can access the network. See Set Up a MAC Filter List for more information about MAC filter.
The wireless security is not following the re-authentication timer setting I specified.
If a RADIUS server authenticates wireless stations, the re-authentication timer on the RADIUS server has priority over the setting in the Zyxel Device. Change the RADIUS server’s configuration if you need to use a different re-authentication timer setting.
I forgot the WiFi password.
• If the Zyxel Device is connected to the NCC and registered, the WiFi password can be found in Configure > Access points > SSID advanced settings > Choose the SSID in the NCC portal.
• If the Zyxel device is in standalone mode, you can change the WiFi password by going to Configuration > Edit SSID Profile > Edit Security Profile in the Web Configurator, selecting Personal, and entering the new password in the Pre-Shared Key field.
I cannot import a certificate into the Zyxel Device.
1 For My Certificates, you can import a certificate that matches a corresponding certification request that was generated by the Zyxel Device. You can also import a certificate in PKCS#12 format, including the certificate’s public and private keys.
2 You must remove any spaces from the certificate’s filename before you can import the certificate.
3 Any certificate that you want to import has to be in one of these file formats:
• Binary X.509: This is an ITU-T recommendation that defines the formats for X.509 certificates.
• PEM (Base-64) encoded X.509: This Privacy Enhanced Mail format uses lowercase letters, uppercase letters and numerals to convert a binary X.509 certificate into a printable form.
• Binary PKCS#7: This is a standard that defines the general syntax for data (including digital signatures) that may be encrypted. A PKCS #7 file is used to transfer a public key certificate. The private key is not included. The Zyxel Device currently allows the importation of a PKS#7 file that contains a single certificate.
• PEM (Base-64) encoded PKCS#7: This Privacy Enhanced Mail (PEM) format uses lowercase letters, uppercase letters and numerals to convert a binary PKCS#7 certificate into a printable form.
• Binary PKCS#12: This is a format for transferring public key and private key certificates.The private key in a PKCS #12 file is within a password-encrypted envelope. The file’s password is not connected to your certificate’s public or private passwords. Exporting a PKCS #12 file creates this and you must provide it to decrypt the contents when you import the file into the Zyxel Device.
*Be careful not to convert a binary file to text during the transfer process. It is easy for this to occur since many programs use text files by default.
Resetting the Zyxel Device
If you cannot access the Zyxel Device by any method, try restarting it by turning the power off and then on again. If you still cannot access the Zyxel Device by any method or you forget the administrator password(s), you can reset the Zyxel Device to its factory-default settings. Any configuration files or shell scripts that you saved on the Zyxel Device should still be available afterwards.
Use the following procedure to reset the Zyxel Device to its factory-default settings. This overwrites the settings in the startup-config.conf file with the settings in the system-default.conf file.
*This procedure removes the current configuration.
1 Make sure the Power LED is on and not blinking.
2 Press the RESET button and hold it until the Power LED begins to blink. (This usually takes about ten seconds.)
3 Release the RESET button, and wait for the Zyxel Device to restart.
You should be able to access the Zyxel Device in standalone mode using the default settings.
Getting More Troubleshooting Help
Search for support information for your model at www.zyxel.com for more troubleshooting suggestions.