So, just to be sure – the prompt you see after you enter your email address and master password matches this in “wording”:
?
(If not, please specify what you see, or if you can, post a screenshot of it – but make sure to redact personal information if necessary).
If it’s indeed 2FA you set up for your Bitwarden account, then maybe the 30-day-“remember me” period just expired. Getting asked for 2FA, when you set up 2FA, is in itself not unexpected.
In your original post you wrote:
… so, I’m a bit confused now if you either also can’t login on the web vault and desktop app – or if it works without any issues?
And from your original post:
Do you get any error message? If yes, what does it say?
Hm, could you please try to update / sync the current time both on your phone and on your computer. – On your phone and on Windows it should be in the respective “Settings” sections. (I’ll try to search for a post here which might give some more explanation for Windows, and add it here – PS: Here some more infos for that / on Windows: 2FAS Verification Code isn't working - #4 by grb)
PS: Different section in the Help Sites, but also “true” for authenticator app 2FA itself – the issue of the “synced time” and TOTP codes: Integrated Authenticator | Bitwarden