Google PAY fixes

Newest FIX for GPay - https://t.me/Mix2sArsenal/283
If that doesn't work, then feel free to try the fixes bellow

https://forum.xda-developers.com/xiaomi-mi-mix-2s/development/rom-pixel-experience-t3872863/page58

This works for someone:

1. Uninstall Google Pay - then clear cache data for Google Play Services

2. Reboot to Recovery and install Magisk v.19 Beta from here:
https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445

3. While in Recovery, go to Advanced > File Manager. Browse to /data/data/com.google.android.gms and rename it to com.google.android.gms.bak - then reboot.

4. Now open Magisk (make sure both are up to date) and Magisk Hide the following: 

- Google Play Services

- Google Play Store

- Google Services Framework

- All Bank Apps (N26, PayPal etc)

5. Reinstall Google Pay from the Play Store (don't launch), go also hide that in Magisk

6. You are done - open Google Pay and add your card - it should work just fine now.

If doesn't work try this guide (Thanks Bollex))

https://forum.xda-developers.com/apps/magisk/magisk-google-pay-gms-17-1-22-pie-t3929950