error: 'Access denied for user 'ggpo'@'localhost'

[teatocoffee]

Almost there.
ggposrv started.

Try to start ggpo client.
When I try to login,I got "lost connection" dialogue.
There ggposrv.log told that ggposrv detected connection from client.
"error: 'Access denied for user 'ggpo'@'localhost'
Noobie to mysql.I think maybe mysql needed to be configured.
But how?Howto add a user "ggpo"?password?
Maybe I still need the login account setup.Still need help.
The mysql is MariaDB.
Thanks.