Azure Web Test - Failed to create SSL / TLS secure channel when using CloudFlare SSL

I have an Azure website and have a continuous web test setup. The web test runs successfully for the entire hour, but then every hour (on the 3rd, to be exact) it fails for the next hour:

System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.
   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at Microsoft.VisualStudio.TestTools.WebStress.WebTestTransaction.ResponseReceived(IAsyncResult result)

      

        
        
        
      

    

The weird thing is that this error only occurs when using CloudFlare in front of the Azure Website. As soon as I suspend CloudFlare, I don't get any more exceptions. I have verified the difference in certificates in Chrome and the certificate from cloudflare uses AES_128_GCM and ECDHE_ECDSA (Chrome shortcuts as modern crypto), while the certificate I installed on the Azure website uses AES_256_CBC / SHA1 / RSA (which is deprecated from Chrome ) - both use TLS 1.2.

I found this post very similar ( https://social.msdn.microsoft.com/Forums/vstudio/en-US/91e37c9e-e15e-444b-bffb-c221df388692/synthetic-monitors-availability-could-not-create-ssltls -secure-channel? forum = ApplicationInsights ) and even replied to the thread to see if there were any updates. Based on this post, it seems to be a problem with the tools Microsoft uses as part of Application Insights, but mine only happens once an hour at a regular interval and it works great any other time.