How to trust IIS Certificates for Development

 Type the following on a command line 

> dotnet dev-certs https --trust

If you're accessing the dev site from another computer or device, via an application, you can disable ssl certificate checking in the client app with...

HttpClientHandler handler = new HttpClientHandler();

handler.ServerCertificateCustomValidationCallback = ( message, cert, chain, errors ) => 

{

if(cert.Issuer.Equals("CN=localhost"))

                {

return true;

                }

return errors == System.Net.Security.SslPolicyErrors.None;

};

Notes about Android and Xamarin

Requires TLS 1.2

The default AndroidClientHandler supports TLS 1.2, but only for Android versions greater than 4.1

If an Android version is needed that is lower than 4.1, then we'll need to use the HttpClientHandler which supports TLS 1.0.  It is slower and increases the package size.

Notes about iOS and Xamarin

Requires TLS 1.2

The HttpClient uses NSUrlSession, this is the default and supports TLS 1.2

Alternatively, you'll need to use CFNetwork for older iOS versions