Trados 2021 subscription keeps deactivating itself

I made the mistake of buying Trados 2021 as an annual subscription. Once or twice a week, when I fire up Trados, I get an error message saying I have "used up all my activations" and can't use Trados anymore. This seems to resolve itself randomly, sometimes after hours. I hate  losing those hours when I need to work.

I have found no way to reliably get it to re-active itself. Logging out, restarting Windows, switching my VPN off - sometimes when I keep trying these in random order, it will eventually allow me to activate it via language cloud login again. But it can take hours.

I have never, ever used Trados Live, I only ever use the desktop app. And when I click "SDL Account" in the login screen in Trados itself, it says I don't have the rights to that account.

I have raised this issue with SDL support several times before, and they have never been able to explain why this happens or how to fix it.