I suddenly stopped getting achivements.

I created a survival world where at first everything is okay since I received achievements just fine. (I played peaceful survival, no coordinate on, nor cheats.) A few days ago, I noticed that my achievements are still unlocked both in Minecraft Achievement and Xbox. I invited a friend to my world and she unlocked an achievement meanwhile I still haven't been able to unlock any of them. I don't know if it is the world or the achievement itself the problem. But I really hope I don't have to create a new world. I googled the problem, and people suggested to reinstall or check internet connection or reattempt the achievement. I've done all of them but still to no avail... Two of the pictures attached, my last feed. The other picture is the achievement me and my friend tried together but ended up only her getting it. I tried twice.