I just received this same error. The problem is its not connecting to your plex server and timing out. I am not sure how overseerr updates IP address's but doesnt seem to have auto updated my IP(power outage reset my ip) after this latest update. My fix was i went into appdata\overseerr\settings.json. Under "plex" there is an "IP" setting which is not my current network IP, it was my previous IP. Grab your new IP (whatismyip.com) and replace the old IP. Save the file and reload Overseerr container. Should work. Good luck