1. Are you using Counter-Strike from Steam? If is a nonsteam Counter-Strike, this error is normal.
2. Is sv_lan 1 ? If yes, type sv_lan 0 in server.cfg / server console.
I recommend you to reinstall the server by this tutorial: https://steamcommunity.com/sharedfil.../?id=729345010
After that, install amxmodx by installer in cstrike directory, create a start.bat file with this line:
start hlds -game cstrike -console +maxplayers 32 +map de_dust
Start the server with this start.bat
I tested today and is working for me.