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:

pls explain it step by step

1. Turn your server back online. You can ask your server provider how to do this if they do not provide a simple button for you.
2. Enter the correct information. If you're not entering the correct IP or port, there is no reasonable expectations of it working.
3. Open the port in your firewall.