SQL Server Reporting Services: External Images from API not loading in report

Question

We have an internal SSRS report that we recently updated to utilize a new API that replaces an existing service used to display images. The original API was hosted internally while the new service is hosted in our new Azure environment. We updated our SSRS report to utilize the new service and can run that report in our local dev environments, but when we deploy to our staging server (running SQL 2014 on a Windows 2012 R2 box) the pictures don't load and we find the following error in the SSRS log files (I've removed the URL for security reasons):

An error occurred retrieving the external resource The underlying connection was closed: An unexpected error occurred on a send.

After doing a Wireshark capture, we found that SSRS is initiating connection to the API using TLSv1, while calls to the same API URL in the browser on the server, which render images fine, are using TLSv1.2. I can see that TLSv1.2 is enabled on the server, but how do I force SSRS to utilize that when running this report and reaching out to the new API?

Answer 1

So, found out how to do this and turns out there are some simple registery updates that need to be made to force SSRS to communicate over TLSv1.2. This tutorial helped me out, mainly section 3 which dealt with the SSRS/SQL server: https://techcommunity.microsoft.com/t5/sql-server-support/enable-tls-1-2-protocol-for-reporting-services-with-custom-net/ba-p/318825

Answer 2

I don't have enough reputation to comment, but please make sure and read all the way down to the comments on @DavidCoxsey's answer, I didn't notice the .NET 4.5 comment at first and spent way to long waiting for Microsoft to get back to me.