C# service cannot connect to web service after server upgrade

I am using HttpClient.PostAsync to call a REST web service (Unified Endpoint Management, but I doubt that is relevant) on a remote (internal LAN) server. The call is throwing an exception as follows: 10/15/2020 5:05:25 AM An error occurred while sending the request. 10/15/2020 5:05:25 AM at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() 10/15/2020 5:05:25 … Read more

How to setup https when developing localy with webpack and hosting on Azure in Docker container running ASP.NET Core

I am hosting on Azure and have it configured to only allow https. The backend is running ASP .NET Core in a Linux container. The webserver (Kestrel) is running without https enabled. I’ve configured Azure TLS/SSL settings to force https, so when users connect from the public internet, they have to use https. I have a cert that is signed by a cert authority and it’s configured in the Azure App Service -> TLS/SSL -> Bindings settings.

The client and server cannot communicate, because they do not possess a common algorithm – ASP.NET C# IIS TLS 1.0 / 1.1 / 1.2 – Win32Exception

I have an issue with a C# PayTrace Gateway. The below code was working fine until yesterday when I believe they turned off SSL3 due to the Poodle Exploit. When running the code below we got the following message. The remote server has forcefully closed the connection. After doing some research on the problem we determined that because our IIS Server 7.5 was configured to still use SSL3, C# defaulted to SSL3, which PayTrace would forcibly close the connection. We then removed SSL3 from the server. Which then lead to the following error:

Check ssl protocol, cipher & other properties in an asp.net mvc 4 application

Because of compliance reasons we have to switch off the support of some ciphers and SSL2 on our webservers. This is not really a problem, but we would also like to inform them, after their successful login into the website, that we suggest switching on TLS 1.2 in their browser in case they are not already connecting to the server with TLS 1.2. So the question I have is: