What should I do in case of a "current customer does not have an active cart" error?

If your buyer is not redirected to the payment page and encounters the error current customer does not have an active cart, this is not an issue of our module but a bug on the Magento side.

The attribution of an order notification e-mail in the Magento Back Office generates this error.

Deleting the notification may solve the problem while waiting for the bug to be fixed.