Hi all, just setting up the stripe for rsformpro for our cycling club and I find that the popup is open for around 2 seconds before redirecting to the 'thank you' page and showing a system error message

Stripe error: Could not determine which URL to request: Stripe\Token instance has invalid ID:

It's probably me doing something daft as we have this working fine on another site with the same host. Could you take a quick look and give me the benefit of your experience please?

Admin note: This issue was imported form the old site (we got the attachment).