Microsoft Office Add In Error

Same issue here, starting this morning. All of a sudden every add-in I use is gone from Word and I can't get any of them to load. In my case that's mainly Spellbook, so this goes well beyond one add-in.

What I've checked so far: I'm on Microsoft 365 Insider, Current Channel (Preview), Version 2609 (Build 20430.20048). "Update Now" says I'm up to date, and all connected experiences are turned on under Privacy Settings. Since several unrelated add-ins stopped working at the same time, it looks like a problem with the add-in platform itself, possibly in the current Preview build, rather than with any single add-in.

I rely on these add-ins every day in my law practice, so right now I can't work normally. If anyone from Microsoft can confirm whether this is a known issue with build 2609, or if anyone has found a fix, I'd really appreciate hearing about it.