Might be a dumb question but can I use a yubico key for more than one device?

I was surprised to see that while I was logging in they were still trying, unsuccessfully.

The successful ones are mine, I have logged in just to check on attempts.

I’m seeing Poland, Germany, Turkey and China.

What’s more annoying is that it’s been happening since January 21st and no notice from MS.

Geo block would be great on unsuccessful logging in.

First time it’s happening to me, makes me feel uncomfortable.

So looking back at Sign-in history it started back on January 21st, trying from China to Germany, Turkey.

Activated yesterday, using MS Authenticator now, before I would get code on my email to verify and authenticate.

With a few steps.