Uncaught ReferenceError processing Stripe using PMPro

Hi,
I’m having an issue processing Stripe on my WordPress site on the Kleo theme.

I get a warning telling me to fill out all missing fields, even though they are all filled out properly. And the credit card number field turns red.

Using the inspector in Chrome, I get this error:
Uncaught ReferenceError: Stripe is not defined at ?level=5:124

This is my site with the problem:
https://norskmodell.no/kontoinformasjon/betalingsside/?level=5

I’m using the Paid Memberships Pro plugin to handle payments. It has been working fine in the past, but I just discovered now that it hasn’t been working for the last couple of months.

I’ve tried deactivating all plugins, and I have tried deleting and reinstalling PMPro, the issue remains.

Any help on this issue would be greatly appreciated.

Thanks