I’ve been using Plex for a few years, with few issues (thank you!). The Plex Media Server is installed on my PC. We use the Plex app on an Xbox One, and an Android device with Chromecast, all on wifi.
For the last week or so, using Plex this way results in our internet disconnecting completely - i.e. all wifi and Ethernet devices have no internet.
The problem doesn’t resolve unless I restart the modem (TP-link Archer D7). Some people seem to have luck with flashing their modem, but I don’t think this is an option with mine.
Is there anything else I can do?