I use Google pay, a lot of times every day with several payment cards. It does occasionally throw a wobbler. I think it's probably linked to issues with the NFC on the phone as opposed to the app because when it happens it affects other things like other payment apps such as sum up machine or tap card to phone to receive payments etc. There are 3 main ways which I have found that fix it. 1 Many cards allow a few taps then require a PIN No, so paying with your card and entering your PIN No fixes this for the next few taps. 2 if there is no response from the phone when you present it to the card reader, Try opening google wallet, then click on the card your paying with so it loads the card to your phone screen, then present the phone to the reader which sometimes works. 3 Do a soft reset of your phone I e press and hold the power button and volume down button together and keep them pressed until the phone goes off and restarts until you see the Samsung logo, then release the buttons, as soft rest clears everything and reloads everything so fixes a multitude of gremlins. Also always have a backup payment card with you to avoid an embarrassing situation 🙂I hope this helps
