Hello,
We would like to apologize for the trouble.
When you are in the testing phase, then you need to make sure that you have enabled the test mode from WP Travel > Settings > Debug
https://prnt.sc/rrdg3x
Also, you should always test at the amount equal to 10 or more. So please check by setting the price for more than 10.
Further upon inspecting your site, we found a lot of console error and one of them in displays that your client ID is raising the issue. So make sure you have added the correct keys in the backend.
If the issue still persists after this then kindly let us know.
Thank you.