Adding a public key to ~/.ssh/authorized_keys does not log me in automatically

Question

I added the public SSH key to the authorized_keys file. ssh localhost should log me in without asking for the password.

I did that and tried t

Answer 1

I had this problem when I added the group of the login user to another user.

Let's say there is an SSH-login user called userA and a non-SSH-login user userB. userA has the group userA as well. I modified userB to have the group userA as well. The lead to the the described behaviour, so that userA was not able to login without a prompt.

After I removed the group userA from userB, the login without a prompt worked again.