error: userauth_pubkey: could not parse key: Invalid key length [preauth]

john@ubuntu18:~$  ssh-keygen -l -f ~/.ssh/authorized_keys
4096 SHA256:PuhB9Q9aZFEIXjm3OQHLpAkLoZ6FxGG3WYs1anMIkRA key2018 (RSA)

john@ubuntu18:~$ ssh -V
OpenSSH_7.6p1 Ubuntu-4ubuntu0.2, OpenSSL 1.0.2n  7 Dec 2017