Progress & Achievements not being unlocked on MCC

So by now I think I’ve completed each level on Halo CE at least three times each on legendary and yet still none of my achievements have unlocked and not even waypoint says I’ve completed a single level of the game let alone do it on legendary.If anybody knows a fix for this it would be well appreciated,but t this point point I think I’m just about done with CE on MCC considering there’s backwards compatibility now,still disappointed that I’ll probably never get Helioskrill though.