Public key authentication not working with new server

Question

I currently have three AWS instances (all running Ubuntu 14.04 LTS) - as well as the default "ubuntu" user created by AWS, I set up another admin user and use a public key specifically for that user from my laptop (Ubuntu 16.04 LTS). So far so good - never had a problem.

Now, I've just created a new instance with 16.04 LTS. I ended up having to cut a new key pair for the ubuntu user when setting up the server as the original pair used for the other didn't seem to work.

I've created a new user on the new instance and have been trying to get publickey authentication working here, too. I can log in as the new user after connecting as the ubuntu user and using the su command.

I keep getting the following when trying to connect as this user from my laptop:

debug1: Offering RSA public key: /home/horuskol/.ssh/id_rsa
debug3: send_pubkey_test
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.

Note - this is the same certificate I'm using for the other three servers and still don't have a problem there

I've checked permissions on the remote server:

/home/horuskol                           horuskol    horuskol    drwxr-xr-x
/home/horuskol/.ssh                      horuskol    horuskol    drwx------
/home/horuskol/.ssh/authorized_keys      horuskol    horuskol    -rw-------

I triple checked that the authorized key on the remote server matched the local public key.

I've even copied the authorized_keys file across from one of the working servers.

Eventually, I created a new public/private key (id_rsa_2017_01) and copied the new public key to the new server.

Nothing has worked so far.

Answer 1

Thanks to Jakuje who pointed me in the direction by providing details on how to change the LogLevel for sshd

It also helped to return to this after a sleep...

debug1: Could not open authorized keys '/home/horuskol/.ssh/authorized_keys': No such file or directory

Because I'd named the file authorized-keys.

Fixing the filename and everything is all good now.