Stripe integration problem

[theegolf]

I've followed your instructions (with a few tweaks of fonts from Google Fonts and icons from FontAwesome) and everything seems to work fine. However, after implementing the Stripe API for payment, the console keeps showing these messages, and clicking the Checkout button yields no output from the backend even though the backend shows the output (session) from Stripe. What do you think I should do to solve this problem? Thank you