I’ve had the tuner installed and added to Plex for the last few months, no my Plex Pass has not expired. Looking at the recordings it seems it started to fail on midday on 7/25. Going to the Live TV & DVR settings it just shows the standard welcome screen about needed to add a tuner.
Did you try restarting the computer or device plex is on?
Also, using a web browser, access the HomeRun’s admin page. It should come up by simply typing the IP address of your HomeRun device. Does the page come up?
You can install the HD HomeRun app on your device or computer to find out if the tunners are working or not. I know there is no app for Roku, but there’s a Windows 10 app as well as Android and FireOS.
I can access the HDHomeRun from the web browser and everything seems fine, even checked the log file for issues. So I unplugged the HDHomeRun EXTEND for a few hours and Plex immediately found it. No idea why it was having trouble but looking at when the recordings stopped it looks like after a Plex Server update it failed to find the tuner.