How to set Proxy for Shiny Server on RHEL


I have a shiny server (not pro) install running on a RHEL AWS instance. The application that the server runs is trying to reach out to the internet to download CSS files. Unfortunately this instance has to go through a corporate proxy to get to the internet.

My question is, how do I configure shiny server (or the shiny application) to make its calls via the proxy server?

*Warning in file(con, "r") : *URL '': status was 'Couldn't connect to server'

*Warning: Error in file: cannot open the connection to ''

*78: file
*77: readLines
*76: shiny::includeCSS
*71: material_page

Sidenote: My AWS ELB is able to make the app accessible on my local network. I do not wish to interfere with this in any way.

Thanks for reading. Any help you can offer is much appreciated.