Hint:
The correct name for LibMediaProxy (mentioned in Shadowfen's answer) is LibMediaProvider
But I actually do not have ANY issue with that library nor any addons using it, so if you got errors I guess youa re using old or outdated or non compatible addons?
!!! Disable addons like BugCatcher !!!
If you got those enabled they will hide error messages and you won't see any relevant ones, this might be also the reason why all your addons all of sudden freak out because 1 central library (LibMediaProvider e.g.?) got an error thta is used in many addons but Bug Catcher hides that and you only see following errors of other addons in the end.
Simply do not use such bag catching and hiding addons, they make our lives very hard and we cannot help you if you use these!
Only way to solve errors is: If you see errors, report them. And not hiding them.
Also use LibDebugLogger to collect all errors properly at best and report us the LibDebugLogger file then here
https://sir.insidi.at/or/logviewer/ so we can see all errors + loaded addons at a glance, from login to end of play.
That makes it way easier to help.
Described here:
https://www.esoui.com/forums/showthread.php?t=8858
"How to report a lua error message to the developers"
-> LibDebugLogger and DebugLogViewer