SoloLearn Challenges

Question

I and One of my friends was challenging each other in Java, after 11 challenges, this thing popped up. Can someone please tell why?
https://www.sololearn.com/post/521821/?ref=app

Answer 1

You might be having some challenges pending from the opponent side, and their is some limit before you go for more challenges, previous challenges needs to finalized..
I exactly don't know the limit, but I had also faced it