There is no failure in sending the email if the credentials are correct.
But still there is an invalid log message.
config
Debug=YES
root=test@test.com
mailhub=test.com
FromLineOverride=YES
AuthUser=config-user
AuthPass=config-pass
AuthMethod=
Send Mail Command
echo "hello" | ./ssmtp test@test.com -au test -ap test
Log
Set Root="test@test.com"
Set MailHub="test.com"
Set RemotePort="25"
Set FromLineOverride="True"
Unable to set AuthUser="config-user"
Unable to set AuthPass="config-pass"
Set AuthMethod=""