I tried to pay for public toilet at Dresden Hbf which is run by Sanifair like at many other places in Germany, and the MC card did not work. On the screen was shown “Processing card” and nothing happened, until the lady came and said that I have to pay by coin, and cancelled the transaction.
The App does not show any informaction about this transaction.
My mom’s MC card does not work with Sanifair too.
BUT, the green Mastercard from TransferWise works with Sanifair!