It can be either internet, or the power of the device.
Puzzle Battle Mode Crashes on iOS App During Match

It can be either internet, or the power of the device.
No, I have full wi-fi bars and I have updated my iOS app to the latest version today.
I have never had any app crash issues via desktop version though, regardless if its mobile or via computer.

Ok, just deleted and reinstalled the app, plus power cycled my device. Still the same issue with the Puzzle Battle Crashing on iOS app.

https://support.chess.com/article/295-how-do-i-report-a-bug-or-make-a-suggestion
Hi,
Maybe worth reporting as a bug with support and they will get back to you.
Hello all,
I am having issues with the Puzzle Battle Mode Crashing on iOS app during a match. I was in the middle of a match when suddenly the app made weird sounds as I was making a move, followed by a crash. Now, I'm trying to create a puzzle battle match via my iOS app but it is not pairing me anymore. Is anyone else having this problem?