Plex says it's playing, but the player isn't advancing

Server Version#: 1.42.2.10156
Player Version#: 1.110.0.351-4e48eb83

According to Plex, the video is playing normally. But on my PC, all I see is a black screen with a frozen frame that doesn’t advance at all. My PC is compatible, so I don’t understand what’s happening. Sometimes when I download the video, it starts playing normally, but not always.

A reinstall fixed for like a half an hour but after that stop working again. 1GB upload and download so it’s not internet