My rank won't progress.

Games Halo 5: Guardians
1

I love playing Breakout but I can’t progress I got stuck at platnuim 6 and went on a 6 win streak and nothing happened.
NOW I’m at plat. 5 and it won’t go back up.
It would seem only loses effect this. I can’t find any explanation…

My rank won’t go up only down.

2

This isn’t a bug OP. Have a read over the pinned Matchmaking Feedback threads in the Matchmaking forums. Dr. Menke has detailed out how the ranking system works, if you still have queries then feel free to leave a comment there