Halo 2 Coop no proggression for player 2

So me and my friend decided to do Halo 2A on legendary and after few days of playing we finished resulting in him as a host getting the achievements and me a guest having no progress on mission list what so ever.The only thing that I found weird while playing was every time we finish a mission on my screen I would load the same mission that we finished but we would continue with the campaign.