how to fix this ?

One of the following suggestions may help you:
Your server is currently offline.
GameTracker needs your server to be online before you can add it to our database. Please restart your server and make sure it's up before hitting ADD SERVER again.
You entered the wrong query port.
Please update your query port and hit scan again
Your server is firewalled.
Please turn off any firewall you have that may block scanning or whitelist the gametracker scanning IP addresses:
208.167.225.11
208.167.225.12
208.167.225.13
108.61.78.147
108.61.78.148
108.61.78.149
108.61.78.150

Due to the vast amount of abuse that has originated from you, it's probably safe to say you are, again, trying to add one of your many banned servers. I am very sorry for the inconvenience you've caused yourself.