IdentityServer4 Correlation Failed Error with External Provider - identityserver4

Question

I am attempting to integrate Ping Federate as an external OIDC provider for my IdentityServer4 instance. When I initiate the external login flow I am getting the following error:
System.Exception: Correlation failed.
at Microsoft.AspNetCore.Authentication.RemoteAuthenticationHandler`1.<HandleRequestAsync>d__12.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at IdentityServer4.Hosting.FederatedSignOut.AuthenticationRequestHandlerWrapper.<HandleRequestAsync>d__6.MoveNext() in C:\local\identity\server4\IdentityServer4\src\IdentityServer4\Hosting\FederatedSignOut\AuthenticationRequestHandlerWrapper.cs:line 38
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.<Invoke>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.<Invoke>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at IdentityServer4.Hosting.BaseUrlMiddleware.<Invoke>d__3.MoveNext() in C:\local\identity\server4\IdentityServer4\src\IdentityServer4\Hosting\BaseUrlMiddleware.cs:line 43
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()
I'm kind of stumped on why FederatedSignOut is even being called. Any ideas on what I may be missing here?
Here is the AddAuthentication configuration:
services.AddOidcStateDataFormatterCache();
services.AddAuthentication()
.AddOpenIdConnect("ping", "Ping Federate", options =>
{
options.SignInScheme = IdentityServerConstants.ExternalCookieAuthenticationScheme;
options.SignOutScheme = IdentityServerConstants.SignoutScheme;
options.Authority = "https://ping.domain.com/";
options.ClientId = "IdentityServer4";
options.ClientSecret = "IdentityServer4";
options.TokenValidationParameters = new TokenValidationParameters
{
NameClaimType = "name",
RoleClaimType = "role"
};
});

Answer 1

Add this in the configuration in startup.cs. Its an issue with going from http to https.
app.UseForwardedHeaders(new ForwardedHeadersOptions
{
ForwardedHeaders = ForwardedHeaders.XForwardedProto
});