Fancis,
I found the following in the body of the Click-Link 200 HTTP Response:
{"url":"https:\/\/example.com\/download\/2770587","isSuccess":1}
To me, it appears to be a Javascript redirect that Nginx is unaware of and in which the https protocol doesn't get rewritten.
Is it possible for Nginx to evaluate the body of a response and rewrite a given string (i.e., https => http)?
I think I might be able to use GreaseMonkey or the like to validate my theory.
Thanks, again, for your time and interest.
Respectfully,
Gary