The game in csgo turned yellow because the connection to any official server failed. You can try to check the integrity of the CSGO game first, or start the accelerator to reconnect, specifically:

CSGO monitor can't connect to any official server. Solution 1: Check the integrity of CSGO game;

Find the CSGO game on the steam platform, then press the right mouse button, select the attribute option, and then click the Verify Game File Integrity button in the Local File tab;

Wait for the verification to be completed, and then try whether the game can connect to the server, but you usually need to restart steam to solve the problem.