Well I solved my problem. When I upgraded the site to https, I had failed to change the site URL in the Xenforo settings from http. Once I changed the site url to https, the Stripe payments began working again.
Everything appears to work fine through Stripe up through getting the green checkmark. Then my browser warns that submitting the form will be unsecured and do I want to proceed. If you click yes, you go the the error page with "This action is available via POST only. Please press the back button...
I’m also getting the same error now. The plugin had been working fine for years but stopped when I upgraded my whole site to use https instead of http. Can anyone help?
Everything works up through a successful Stripe payment but nothing is logged and the user is not upgraded. At the completion of the payment the user was redirected to a page that could not be found. Any thoughts?