Xamarin Android issue connecting via HTTPS to site with self-signed certificate: “Trust anchor for certification path not found.”

I was able to get this to work in both Android and iOS.

iOS was easy, just override ServicePointManager.ServerCertificateValidationCallback:

ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;

For Android I used Bruno Caceiro’s answer from a similar question and a created Dependency Service.

In my Xamarin Forms project I added a simple interface:

public interface IHTTPClientHandlerCreationService
{
  HttpClientHandler GetInsecureHandler();
}

And in my Xamarin Android project I implemented the interface:

[assembly: Dependency(typeof(HTTPClientHandlerCreationService_Android))]
namespace MyApp.Droid
{
  public class HTTPClientHandlerCreationService_Android : CollateralUploader.Services.IHTTPClientHandlerCreationService
  {
    public HttpClientHandler GetInsecureHandler()
    {
      return new IgnoreSSLClientHandler();
    }
  }

  internal class IgnoreSSLClientHandler : AndroidClientHandler
  {
    protected override SSLSocketFactory ConfigureCustomSSLSocketFactory(HttpsURLConnection connection)
    {
      return SSLCertificateSocketFactory.GetInsecure(1000, null);
    }

    protected override IHostnameVerifier GetSSLHostnameVerifier(HttpsURLConnection connection)
    {
      return new IgnoreSSLHostnameVerifier();
    }
  }

  internal class IgnoreSSLHostnameVerifier : Java.Lang.Object, IHostnameVerifier
  {
    public bool Verify(string hostname, ISSLSession session)
    {
      return true;
    }
  }
}

Shared code to correctly set up the HttpClient:

switch (Device.RuntimePlatform)
{
  case Device.Android:
    this.httpClient = new HttpClient(DependencyService.Get<Services.IHTTPClientHandlerCreationService>().GetInsecureHandler());
    break;
  default:
    ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;
    this.httpClient = new HttpClient(new HttpClientHandler());
    break;
}