"Failed to create secure SSL / TLS channel" in Azure web application

My Azure Web Application needs to connect to various servers (with or without SSL). This works fine while I run the application in my local IIS Express or IIS 7.5 on Windows 10.

As soon as I deploy the application in Azure, it stops working on certain servers that require SSL (not all). If I run it through ssllabs , they usually get A, and those that work get B or C.

So, I would suggest that .NET on an Azure instance supports fewer ciphers than local support or something like that?

I tried this

ServicePointManager.ServerCertificateValidationCallback = delegate { return true; }; ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12 | SecurityProtocolType.Ssl3; 

And tried it without any TLS flags, since it was suggested by most people, but it didn’t help. According to the message below, in October it was fixed, but in December.
https://social.msdn.microsoft.com/Forums/en-US/ca6372be-3169-4fb5-870f-bfbea605faf6/azure-webapp-webjob-exception-could-not-create-ssltls-secure-channel?forum= windowsazurewebsitespreview

It also has nothing to do with Cloud Flare.

Any ideas? Or maybe for starters, how do I know which cipher my application uses and what is available?

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Perhaps SSL3 or Tls1.0 are not supported? I had a similar problem, and after switching to this, it all worked:

 ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 

You can use ssllabs to check the protocols you are trying to connect to the servers you are using.

https://www.ssllabs.com/ssltest/

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