Here’s a method on how to install and use Android Pay without any issues on Xiaomi smartphones.
How to fix Android Pay on Xiaomi phone
This method should probably work on many of the devices, including Mi 5, Mi 5s, Redmi Mi Max, Redmi Note 3, Redmi 4, Redmi Note 4 etc… But attention, that author of this tutorial does not guarantee that this method works 100% and we’re not responsible for any possible issues. Please take care and make all required backups!
Download Magisk Manager.
Install this fix via TWRP: Magisk12.0_Hide_fixed.zip
Boot into system and run Magisk Manager.
Enable “Magisk Hide” in the settings.
On “Magisk Hide” screen select and enable required apps.