Like the title says, my achievement is not active 
I finished thw campaign in Heroic lats year I think, but the achievement progress thinks that i fiss one mission!
But if I look in my mission and/or my Career (in game) it shows that I finished the game on heroic.
Can i do something?? Thanks Spartans!
According to your service record you’ve completed the campaign on normal difficulty. Be sure to double check all levels and, if it’s a bug, try completing one of the non-combat missions on Heroic/Legendary again such as Meridian Station, Alliance or Before the Storm.
Ok, I’ll double check, thanks!
Happy Infinite
No problem! Have fun too!