every time I try to play an anniversary map, i get matched with players, a map is voted for, and then I’m immediately sent back to matchmaking when the game tries to load. This only just started happening and its very frustrating. the read playlist works fine, its only in anniversary that get sent to matchmaking the moment the game tries to load.
Are you playing off the Anniversary Disk or via Reach?
If via Reach, re-download the Anniversary Map Pack through your download history.
If via Anniversary, check to see if the disk has any noticeable scratches, if not, attempt to install the game to your Hard Drive, if you get an error during it, the disk is scratched and needs replacing, if you can install it, try playing again.
All of the above should help/fix your problem.