So far I've tried every registry solution mentioned and it seems random if they work yes or no. They have one thing in common, it will only be active once. Same issue starts over after closing Word and restarting.

It's not only Office 365. I'm still on the Office 2016, Version 2407 (Build 17830.20138).

Same issue, same error message. Starting on 8-Aug. "Work Around" is to to start Word, disable the plug-in. in the Add-in enable it again. Close Word, restart and hope … After an average of three times repeating the same, Word is starting with the plug-in.