If you are getting kicked back to the main menu with no real error message it is likely that your connection is dropping… even if just momentarily.
I had an issue with it a while back and the problem was definitely on my end.
I’d say get your game log and post it, or better yet, post in the support section as they will be better able to diagnose the issue and help you resolve it.
Probably this to be honest. I had the problem consistently for a week, and one time it happened 4 times in a row in a ranked match that we were winning (then my team surrendered ).
I actually posted a thread about it lol. http://forums.dirtybomb.com/discussion/36953/randomly-kicked-from-ranked-match-and-left-with-penalty#latest
My ping shot up, but quickly went back down. Sadly, I was kicked once it went back down. The times after that there was no warning of me being kicked, ping didn’t spike or anything, just kept sending me away.