Google pay TEST env used to work, there haven't been any gpay related changes in my project for a year but now I started to get this error. This is on test environment.
I get the error when I press on continue button (on this screen)
I also get these logs:
2023-07-31 16:41:20.318 2792-4169 GmsTaskScheduler com.google.android.gms.persistent E sendWakeUpEvent called on SchedulerClientBroadcastStrategy
2023-07-31 16:41:20.321 3284-9819 Volley com.google.android.gms E [2916] fgx.b: Unexpected response code 500 for https://payments-pa.googleapis.com/payments/apis-secure/ui2/buyflowservice/submit
2023-07-31 16:41:20.328 3284-3632 O2NetworkAction com.google.android.gms E Network Error: java.util.concurrent.ExecutionException: com.android.volley.ServerError
What could be wrong here? How do I solve this?

We had the same issue (and other problems) that were caused by using "NIS" as the currency code instead of "ILS". changing to "ILS" in our case fixed the problems so i would check your country and currency codes.