[SOLVED] UseWsFederationAuthentication - AuthenticationException: The remote certificate is invalid according to the validation procedure

I am getting an error every time I try to run my MVC project on my development box through VS2015 and IIS Express. It uses this code to authenticate against our ADFS server.

app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
            app.UseCookieAuthentication(new CookieAuthenticationOptions());

            app.UseWsFederationAuthentication(
                new WsFederationAuthenticationOptions
                {
                    Wtrealm = realm,
                    MetadataAddress = adfsMetadata
                });

This is the error I am getting in the browser.

[AuthenticationException: The remote certificate is invalid according to the validation procedure.]
System.Net.TlsStream.EndWrite(IAsyncResult asyncResult) +231
System.Net.PooledStream.EndWrite(IAsyncResult asyncResult) +15
System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar) +119

[WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.]
System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) +606 System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar) +64

[HttpRequestException: An error occurred while sending the request.]
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +28 Microsoft.IdentityModel.Protocols.d__0.MoveNext() +453

[IOException: Unable to get document from: https://adfs.DOMAIN.com/FederationMetadata/2007-06/FederationMetadata.xml] Microsoft.IdentityModel.Protocols.d__0.MoveNext() +830 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter1.GetResult() +28 Microsoft.IdentityModel.Protocols.<GetAsync>d__1.MoveNext() +606 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter1.GetResult() +28 Microsoft.IdentityModel.Protocols.d__3.MoveNext() +1332

[InvalidOperationException: IDX10803: Unable to create to obtain configuration from: 'https://adfs.DOMAIN.com/FederationMetadata/2007-06/FederationMetadata.xml'.] Microsoft.IdentityModel.Protocols.d__3.MoveNext() +2226 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +28 Microsoft.Owin.Security.WsFederation.d__c.MoveNext() +772 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__b.MoveNext() +447 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__8.MoveNext() +440 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__5.MoveNext() +266 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +1174 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.d__5.MoveNext() +287 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +937 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.d__5.MoveNext() +287 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.d__2.MoveNext() +272 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +26 Microsoft.Owin.Host.SystemWeb.Infrastructure.ErrorState.Rethrow() +33 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +150
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) +42
System.Web.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult ar) +9791593

It was working and now it doesn't any more....why?

Any thoughts on why this is not working, why the remote certificate is invalid according to the validation procedure (Where is that procedure?), and how I can get this back up and running?