My server is rented from gameservers.com and when I try to add by IP it gives me the following error:

One of the following suggestions may help you:
Your server is currently offline. Server is not offline, as I can join
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. (Still not able to add the server to game tracker.)
You entered the wrong query port. 25030 is the join port and the query is showing as 25031.
Please update your query port and hit scan again

All of the below is not applicable as it's controlled through a server provider.

Your server is firewalled.
Please turn off any firewall you have that may block scanning or whitelist the gametracker scanning IP addresses:
149.28.43.230
45.77.96.90
108.61.78.150
108.61.78.149

Any ideas or help would be appreciated.

Thanks,
Mako

Inadvertently ran across the fix. The Join port and the Query port are now the same

Source: https://www.gametracker.com/forums/forum.php?site=1&thread=150400

Unfortunately, I am in the same position. I was not able to find something to replace my previous hosting, but I still have not given up hope. Eventually, there is a chance that they will suggest a good option here.