Checkout Fails Every Time

Hi all, love nopCommerce so thank you for the system!

I've just set up two instances on a server and they both are failing at exactly the same point (two different shops)
They are hosted behind Nginx so all traffic is http: internally but Nginx handles https: outside of my network, don't think this is the issue but thought I'd mention it

Both sites have PayPalCommerce plugins set up with nice green ticks when I save the settings, have created apps and got the keys, all looks good

So when I buy something, at checkout I hit the PayPal button and the payment wizard opens showing step 1 (address selection). Before this, though I can see what I think is the PayPal popup form which quickly disappears. Back in the nopcommerce checkout page I click 'Next' to move to step two and it puts me straight back at the checkout page again

THis is giving me the impression that the paypal popup is failing and its failure causes nopcommerce to be unable to continue

Q> Can anyone confirm that the paypal payment box appears immediately after clicking the 'Paypal' button on the checkout page?

If so, what things could fail here? There is nothing in the Logs section after this happens

Thanks for any pointers, I've given this a good few hours already and am scratching my head a bit now

you can check application error log from Windows  Event Viewer -> Windows logs -> Application

TheCardProjectUkLtd wrote:

It's by design, after pushing PayPal button the popup form quickly disappears and the default checkout process is continues.

TheCardProjectUkLtd wrote:

Try to disable one page checkout in Order settings, will there be an error (redirect back to the checkout page) in this case? If multi step checkout works correctly, then this error is related to the SSL configuration (Nginx in your case) and one page checkout.
There were several topics about this in the forums, for example here.

Thank you, unchecking the single page version solved the problem, great work you do