"This error comes up when two or more systems are connected online together. When the computers stop sending the same packets the fall out of sync, this error pops up. These synchronization errors happen for various reasons. Background programs obstructing the flow of information, modified game code or maps, or possibly corrupt game files.
First, make sure that you have closed any programs or tasks running in the background as sometimes one of the programs can conflict with the game. Click here for instructions on ending your background tasks.
Failing that it could be any saved maps or corrupted game files. Try uninstalling the game completely, then before reinstalling delete the original game directory and the Command and Conquer Data folder located in the "My Documents" folder. After you have completed that, reinstall the game and immediately patch it. See if that resolves your issue.
If you cannot uninstall the game for any reason click on the link below.