Can you tell me the exact error while making payment?
In the meantime, let's try making a payment on an incognito window.
It is the best place to identify any browser-related issues. You can use these keyboard shortcuts to open one:
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Microsoft Edge: Ctrl + Shift + P
Safari: Command + Shift + N
If it works, you can go back to a regular browser and clear its cache. A piled cache can also be the reason for some unexpected error on the opened pages.
You can also switch to a different browser like Google Chrome, Mozilla Firefox, Safari, or Microsoft Edge as alternative.