Acumatica behind reverse proxy causes issues with GetFile.ashx - reverse-proxy

Question

I am running my dev instances of Acumatica behind an reverse proxy that consists of IIS with Application Request Routing 3.0
For the most part things run and behave as expected, however I have issues with images, e.g. logos, inventory pics, etc. The issue is that upon first load the url delivered to the client is an absolute url. If move between branches then logo url switches to a relative url and the image displays properly.
if you would like an example here is a url to a test instance.
https://2019r2.acumatica.govelocit.com/test20r1
user: admin
pass: P#ssword1
when you login the logo will have a broken link icon
Image with Broken Link
if you switch to a new branch the logo shows.
Working Image
if you switch back to the branch you started with the logo still displays fine. It is just an initial load issue.
Thoughts?

Answer 1

The issue here is that absolute url being built using not current url schema but, the schema the site was called. And since you are calling the site from your reverse proxy via http, the link generated for images is also http, and therefore cannot be loaded. Additionally you are getting the security warning, as the you are calling http content via site on https.
like here
and if you just edit url schema in browser, the image will appear -
here you see the image
There are at least 2 good solutions to suggest:
Point your Reverse proxy on HTTPS site. This is quite a straightforward solution that might however bring a little headache in configuration if your reverse proxy will not like the self signed IIS certificate. It also would not allow to analyze the requests, as all transports will be encrypted.
Another solution is a little more sophisticated and will enable you to call http site and make it thinking you are calling https. For this you would need to set the X-Forwarded-Proto header as https, in your reverse proxy config.
Unfortunately not familiar with Application Request Routing 3.0, for better understanding the NginX proxy location will look like this:
location ~ ^/(MySite){
proxy_pass http://localhost:82; //note, you are calling https here
proxy_set_header Host $host;
proxy_set_header X-Forwarded-Proto https; //here you are tricking the site
}