As far as i see this error ist not caused by your gateway.
The token is a session token for your websession, it secures the client - server connection between your browser and the ttn console webserver. If you just leave the console page it expires after a while.
If a page refresh does not fix this: check the clock on your computer. If the time looks right, also ensure its time zone setting is correct; your clock could be off by many hours if you’re using the wrong time zone.