I can't claim my counter strike 1.6 server. I am changed name of my server in gamepanel but I see this message again:

We were unable to verify that your server name is 'GameTrackerClaimServer'
In order to claim ownership of your server you must temporarily rename it to:
GameTrackerClaimServer
This server is currently named:
Half-Life

Please check your game server config file, restart the server, and try again.

If you change a config, you typically need to restart the server to get it to take effect. After doing so, you may want to join the server to see if it is renamed.