permission denied

Linux: ssh-keygen to check whether ssh private key and public cert are keypair

When using a private key on the client to ssh into a remote server with the matching public certificate in ~/.ssh/authorized_keys, a common failure message from the client is: Permission denied (publickey) The most common reasons for this is private key permissions issues (chmod 600), a misconfiguration of authorized_keys, or trying to send the wrong Linux: ssh-keygen to check whether ssh private key and public cert are keypair