If you are encountering any issues, the first thing you should do is to perform a full power cycle of your ISP.
Prerequisites
If you can, it is better to put the ISP in Standby mode before shutting it down to avoid SD card data corruption.
Instructions
Shut your ISP down using the back panel power switch. You can also use the remote power switch your ISP is connected to.
Wait for at least 30 seconds.
Switch your power switch back on.
A full power cycle can help for minor issues, including those that may be caused by external events such as power surges, power outages, etc…
If the issue persists, you can also try a Factory Reset.