How to understand the reason why ssh connection by key is not established?

Question

SSH

I'm trying to establish an ssh connection between a client and a server using an rsa key. Key generated via ssh-keygen, added to authorized_keys, sshd_config set to PubkeyAuthentication yes . But the connection by key without a password is still not established. Actually the question is where to dig / how to debug?
I ran ssh with the -vvv switch, here is the content of the output:

Answer 1

where to dig / how to debug?

Read /var/log/auth.log (or wherever sshd output is configured) on the server.

Answer 2

Check the permissions on files and folders.