@sumpfgeggi Welcome to the forum!
How long ago did you first register for your Bitwarden account? Was it before August 3, 2022?
When you say “enter”, it is important to distinguish whether you were previously using this “short code” to unlock your vault, or to log in to your account.
Do you have any Bitwarden apps or browser extensions on any computer or other device where you are still logged in to your Bitwarden account (i.e., the authentication prompt has an “Unlock” button instead of a “Log in” button)? If you are going to check for this possibility, it is highly recommended to disconnect the device from the internet before opening the app or browser where you are going to check the login status of your Bitwarden account.