server not found

Hi there,
have been running Plex for 2 years with no problem. Now all of a sudden it will play for approx 30mins and then says “the server is unavailable” but all my internet connections are still connected. If I reboot my router/modem it starts again for a while then the same thing happens. Thought it was my router so went and bought a new one but the same thing happens.

what os? we need more information in order to help you.