I can complete my order?

I have uploaded a screen shot of the screen we get when trying to complete the order? Can you tell me how to fix it please?

If you have successfully connected your PayPal Business account to the PayPal Checkout integration in your form

but you are still getting the error message shown in your screenshot, it's possible that the payments were not successfully processed on the PayPal Checkout's pop-up page.

I have created a cloned version of your form and made a test submission but I was not able to reproduce the issue you are having. Can you give us the exact steps of how we can reproduce the issue, please?