Wireless Local Area Network (WLAN) error "No gateway reply" or "Invalid server name" may occur for various reasons, for example because of mismatching WLAN settings between the mobile device and the WLAN network.

To fix the problem, you can try the following:

  1. Check that your device has SIM card properly inserted and that the device is not in offline mode. When in offline mode, the device has limited WLAN functionality and may not find e.g. the hidden WLAN networks.
  2. Check that you are under the coverage of the WLAN network. Enable 'Show WLAN availability' in the Wireless LAN settings of the device. When this setting is enabled, you should be able to see an indication when a WLAN network is available. You can also use the Connection mgr. or WLAN tool in your device to check which WLAN networks your device is currently seeing. 
  3. Check that the WLAN access point is properly configured in the connectivity settings of your device and that the WLAN security settings match with the settings of your WLAN network. The WLAN networks are typically configured with some sort of security enabled (WEP, 802.1x, WPA/WPA2) and it is important that the corresponding security settings are defined in your mobile device.
  4. If you have other devices already successfully connecting through WLAN, check and compare that the same WLAN security settings are used in your mobile device.
  5. Check that the correct access point is used when trying to connect to WLAN. Go to the web browser settings and select the WLAN access point or destination which has been defined in your device. Try to connect to a web site and check with the Connection mgr. tool if the WLAN connection becomes active.
  6. If your device is using destinations (groups of access points) instead of single access points in the connectivity settings, check that the WLAN access point is at the top of the list in the destination settings (otherwise the device may try to connect through an access point which is higher up in the priority list). 
  7. If you are not able to connect to WLAN even though the WLAN settings are properly configured, reset the WLAN access point (WLAN router) to default (factory) settings and begin defining the wireless network again so that there are no security features, no hidden ssid, no mac filtering, etc. This way you can troubleshoot at which point the gateway error appears.
  8. Disable Bluetooth connectivity in your device while being connected to WLAN. Bluetooth and WLAN operate on the same frequency range and may interfere with each other.
  9. Restore(reset) your mobile device back to original (factory) settings. You can do this from general settings of your device. Please see more detailed instructions from your device user guide. Note: It is recommended to backup the device before resetting it.
  10. Check that your WLAN network is configured to deliver IP address automatically via DHCP to the connected devices. The mobile devices are by default configured for automatic IP and DNS address retrieval from DHCP server. This is the default mode in most WLAN environments but if using fixed IP addresses, you need to configure the addresses manually in the advanced level settings of your phone (phone IP address, subnet mask, default gateway, DNS addresses).
  11. Check that there are free IP addresses in the address pool of your WLAN DHCP server. If there are other devices already connected to your WLAN (e.g. PCs), all the available IP addresses may already be reserved and the phone doesn't get an IP address allocated. Add more IP addresses in your DHCP server settings or release an IP address from another WLAN connected device. Note that switching off the device doesn't yet release the IP address, you should release the address manually (e.g with "ipconfig /release" command in Windows PC) or wait for the IP address lease to expire (which can typically take a few hours).
  12. Check that your WLAN environment is not configured to filter the access based on the device MAC address. If using MAC based filtering, the MAC address of your mobile device must be added in the filter list. The WLAN MAC address of your phone can be checked by typing command *#62209526#.
  13. Check if there are software updates available for your WLAN router and install the latest software.
  14. Try setting up different channels in your WLAN router, especially if there are other WLAN networks in the neighborhood with overlapping channels.
  15. Disable WLAN power saving mode in the phone settings if there's any mismatch in the phone and WLAN router power saving features (use this only as a temporary workaround because it will increase the battery consumption).
  16. With some WLAN routers disabling the QoS (Quality of Service) service may help.

Note that the message "No gateway reply" or "Invalid server name" may occur also because of some temporary network problems, for example when under poor WLAN coverage or when there's some issues or delays at the web server side. In these cases, check that you are under the WLAN coverage area and try the connection again.