Plex Media Server failed to start. error issuing curl_easy_perform(handle):51

Plex Media Server NAS & Devices
1

The Plex Media Server ran very well few years ago until last week the Portal page failed to launch.
Log shown that error
CodeManager: obtaining decoder ‘mpeg2video’
Error issuing curl_easy_perform(handle):51

3

Instead of screen shots, regular logs please?

4

Thank you for the prompt reply. It really surprised that the problem solved after I reboot the router.
While the problem occurred, my home internet connection is fine and the NAS even providing other Internet service properly. Still no idea why but thanks again for the suggestion. It really helpful.