To understand the error, you must understand the infrastructure of Call of Duty 2 on PC. Released in 2005 by Infinity Ward, the game used a centralized master server system powered by GameSpy. When you launched multiplayer, your client would phone home to a master server to validate your CD key.
When you attempt to join a multiplayer session, the game must first confirm that your CD key is valid and not already in use on that specific server. In Call of Duty 2, this process involves a handshake between your local machine and authentication servers that are no longer actively maintained. Consequently, players often find themselves in an indefinite loop where the game "waits" for a response that may never arrive. Common Causes Several factors can trigger this authorization hang: call of duty 2 awaiting key code authorization