May 18 18:41:53 myserver authdaemond: failed to connect to mysql server (server=localhost, userid=mail_admin): Access denied for user 'mail_admin'@'localhost' (using password: YES)
It donīt seems like your mysql-user is allowed to access. Do you flushed your user privileges?
Or do you entered 127.0.0.1 as Host instead of localhost? I think MySQL differs between 127.0.0.1 and localhost.