Hello.
I was using EU version 4.26.2. After this problem appeared I updated to 4.27 with no luck.
After uploading app to google play it says that app uses billing library that is too old and have to move to billing library version 3.0.0.
Everywhere I read about this problem people says UE 4.26 and above uses lib version 3.0.0 but this error still appears