Google error message when i try to upgrade to "life time upgrade".

Expected behavior

I expect that clicking on "life time upgrade" in order to make payment for upgrade, should bring up a means of payment.

Actual behavior

Clicking "life time upgrade" brings up an error message.

How to reproduce

1. Download QKSMS from F-droid
2. Launch the application
3. Click on menu on the top left of the application
4. Go to "QKSMS+"
5. Click on "Life time upgrade", an error message comes up.

• Device: Tecno Camon CX
• Operating system: Android 7
• Application Version: version 3.0.5

Recording Of The Bug