To troubleshoot the issue you might encounter with your WL WN538A8 Router device, follow the further instructed steps.
You need to verify first the internet connection from your modem device is perfectly working or not. If there is any issue then you need to connect your ISP for a solution. In case there is no issue then move ahead to detect the issue.
To verify the cable connection you have to check every cable connected with the router. If any connection is loose or a damaged cable is there, it may create trouble. Do the needful to address the issue.
If yet the issue is there, then you should try rebooting your device. Rebooting will resolve temporary issues in the network.