MacOS unable to login after user folder moved to external SSD

I‘m running MacOS Monterey on a Mac Mini M1. I wanted to use an external SSD for all my data. Therefore, I moved my users folder to the SSD and then changed the account settings to point to the new location. When I then restarted the computer, I got the error „You are unable to login to the user account at this time“ at the login. It looks like there’s some data on the SSD that’s required for the login but the SSD can’t be accessed.? The setup (same computer and external SSD) used to work. But after the last OS update, there was again a new user folder on the Mac‘s HDD and I had to change the settings again which introduced the problems. There’s no other user account set up. Any help is mich appreciated!