I am not very familiar with ssh and I am afraid I made a disastrous mistake.
There is an old server which used public key authentication. My public key was in the authorized keys, so I was able to access it. The user was the default 'ubuntu' user and I am pretty sure that it had no password.
I disabled the public key authentication, setting the "PubkeyAuthentication" to "no".
Now I am locked out as when I type
ssh ubuntu@[host_IP]
I need to give a password and then I get
Permission denied, please try again
I think there was no password for this user. I am sure that I didn't have to give any password for sudo
commands
Is there any way to access the server again?