"You have lost connection to the server"

What you were expecting to happen, and what actually happened?
I was expecting to be able to play an arena game. In fact I got this error message in a popup, and when I restarted the client it gave me an arena loss (another bug that hasn’t been fixed for months).

What are the steps to make it happen again?
Play on android. I’m having this happen multiple times a day

Do you have any screenshots or video you want to share with us so we can see the problem? Attach them to your post!

I’m sure I’ll get another one soon.

A couple of questions:
What Android device are you using?
What OS is your device using?

Nexus 6 running Android 6.0.1