So we're doing a credit card transaction and it comes back from paypal on
the return trip with that error (on our end). The reason is that the return
URL is:

http://www.domain.com:443/....

so its trying to access port 443 via http.

I won't know till tomorrow, but I hope that we can adjust the return URL to
correctly be "https://www.domain.com... than it works as it should.

My question is, should I put something in the Nginx configuration file that
if someone tries to access "http" using port 443, redirect them to https?
If so, how? Is that the correct way of going about it outside of correcting
the return URL (which of course would be the ideal way), but in general,
should requests coming to http://www.domain.com:443 be forced to HTTPS?

Thanks!