The only error that was thrown was that one or more errors had occurred and in the inner exception of that it said that ”The underlying connection was closed: An unexpected error occurred on a send.” and at some other level ”An error occurred while sending the request”. Not much to go on.
I was pointed to this page by Thomas Sandsør on Facebook (from Microsoft, somewhat safe to open :)) saying that TLS 1.0 and 1.1 will stop working at some time and if you move to .NET 4.6.2 you will be fine.
Now, that didn’t quite happen since I still had the same issue running .NET 4.6.2. Digging continues and to my surprise I actually found something at stack overflow (maybe a bit less safe to click on) where they said that you should be able to connect by just using ”https” in the connection string but I also found this line of code:”System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;”
Adding that to my code, which it seems I can do pretty much anywhere before I do a call, solves the problem and I’m again able to connect and retrieve data from the Web API.
The funny thing is that I was able to get a token all the time so the authentication actually worked, it was just the GET and PATCH and so on, I guess since the program crashed badly at the GET so I really don’t know about the rest but it seems plausable.
Hope this helps.
Developer at CRM-Konsulterna