Halo 2 in 3 hours not working

I did halo 2 in 3 hours with 10 mins to spare and i still dont have my achievement and my times aint saving on this site why??

only thing I can think of is that you had The bandana skull or Scarab skull on, but I don’t think you did that. IDK bro

Or you used the checkpoint method and if you do that at the last checkpoint of a level it won’t register your time. You will have to replay those levels.