Anyone have any experience with Online problem?

Does anyone know why i can’t play halo reach map when im in 3rd party Rounter? When i play other game, it went so perfectly fine! but Halo reach wouldn’t let me play at MOST % of the map, any idea ladies and gentlemen? Do you guys think the Halo sever don’t provide at some other place out of countries? or it just that the bug is blocking?