CS: GO server errors can be due to Windows Defender Firewall blocking the game connecting with the server. Click the Turn Windows Defender Firewall on or off link. Select the Turn off Windows Defender Firewall options, and click the OK button.

How do I fix Steam not connecting?

Restart Your Steam Connection. If you receive the network connection error, you may need to restart Steam. To do this, select Steam > Go Online > Connect to the Internet > Restart Steam. When you receive the Cant connect to Steam error, you have the option to Retry Connection or Start in Offline Mode.