The gateway does not detect any nodes

If the gateway has its linked/unlinked list empty despite the fact there are nodes that shall be visible then the reason may be the gateway has no access to SNTP server and has no correct real time.

The time set in the gateway can be checked in Advanced -> Details. It shall be current UTC time.

The gateway with no access to the SNTP server will display date from year 1970.

If it is incorrect then the SNTP server settings must be corrected as described in Network time (SNTP/NTP settings)