It would be SSH miss configurationmisconfiguration at server end. Server side sshd_configsshd_config file has to be edited. Located, it is located in /etc/ssh/sshd_config.
In
In that file, change variables
'yes'
yesto 'no'nofor ChallengeResponseAuthenticationChallengeResponseAuthentication, PasswordAuthenticationPasswordAuthentication, UsePAMUsePAM'no'
noto 'yes'yesfor PubkeyAuthenticationPubkeyAuthentication
Based on ... (linkLink to original source is now pointing to spam and was removed).