If your database details correct :
in putty, type 'ps -u root' and enter
(if you are using root user)
it will show u the list of processes, make sure there is no multiple char-server , map-server, or login-server processes that ongoing.
IF there are multiple processes for any of that process listed above ...
REBOOT your VPS
might be because of you start server many times or have some processes that 'stuck/hang'
solution :
login vps , type 'reboot' and enter.
vps will be restarted. Wait for a minute and login again , and start your server.