Not been able to get the checkout to work

I have set up my WooCommerce pages for my site but I have not been able to get the checkout to work. I set it up to take Credit Cards and process through PayPal but it generates an error when I click on the [Credit/Debit Cards] button, see attached. Please quote me to fix this issue.

I fixed the PayPal integration issue but there is still one thing I would like to see if I could get you to change…
After processing the payment, the landing page (see attached) looks good but the comment on the landing page is:
“Thank You. Your order has been received.”
Would you be able to change it to say:
“Thank you for your order. If you have already submitted your measurements and pictures, your brace order will now be put into production. Fabrication is typically 3 business days and shipping is 2-4 days. We will send you an email when the brace has shipped. If you have not yet sent us your measurements and pictures.