Permission Denied with SSH Keys

Hello Gitea friends,

I am facing an issue with SSH access to repos. I am the admin and I was first to create a new key and register it with my user + verify it. We are using the embedded SSH server. Gitea is running in a docker container on Ubuntu.

My SSH key that I created a few months ago works. However, new keys that me or other users create and add to the user profile do not work. I checked and the new keys show in the database with type 1 so they should be available for users to clone, pull, push etc. I tested with my user to create a new key on the client, added it to my user, verified it successfully. But when I then use this key i get permission denied.

These are the verbose SSH logs for the command ssh -T -vvv -p 2222 -i ~/.ssh/test3 git@git.domain.com
debug1: Next authentication method: publickey
debug1: Will attempt key: test3 ED25519 SHA256: explicit
debug2: pubkey_prepare: done
debug1: Offering public key: test3 ED25519 SHA256: explicit
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
git@git.domain.com: Permission denied (publickey).

Do you have any ideas for help here? Thank you very much