Often while playing, for no reason in particular, I will get the Unknown Error message and the game will freeze. This can be fixed by force closing the game, but you functionally lose your turn, which can often mean a cheap loss
This is happening for me as well.
Hello support, I had the same issue yesterday during the championship event. It made me instantly lose which ruined my run! I hope a refund of the entry fee is somehow possible.
I also have this issue almost every time I play the game. It happens in the middle of a match. Tonight it happened 3 times, resulting in a match loss.
It sounds like you may need some more troubleshooting advice, please submit at: https://magicspellslingers-support.wizards.com/hc/en-us/requests/new and select 'Technical Troubleshooting'.