If you have OpenHAB on Proxmox or any other virtualization and it sometimes fails to grab RTSP stream and create snapshots, then there is high chance that everything is fine with the camera and network and the problem is within your server hardware. I was investigating this matter a lot and came into this simple conclusion.

If camera does not have built snapshot URL coming from ONVIF (like on EasyCam WiFi with both ONVIF and Tuya) then your OpenHAB will try to make one from RTSP stream with ffmpeg. It starts ffmpeg process which will periodically (in my case every 2 seconds) grab frame and make JPEG out of it. However if you run your OpenHAB on some older hardware like I do (i3-4150 with 2c/4t) there is a chance that 100% utilization spikes on one vCore is too much for it… really. I noticed that with those CPU util spikes come also other connectivity issues and migrating OpenHAB to different server within the same cluster solved almost 100% the problem.

Instead of no image every minute or so now it misses snapshot every few hours. It might do this still because of WiFi signal strength and not because of lack of computational power on server side. There might be also case when camera is buy doing other things. Hikvision cameras notifies you with proper XML error code about this. Maybe there is also the case with EasyCam cameras. Who knows.