Blazor Web Assembly App Identity Server not working in production

Error:

I’ve created a simple Blazor Web Assembly project hosted inside a .NET Core App using .NET 5.0 RC1 Framework and I added the authorization during the wizard in Visual Studio 2019 Preview. It works perfectly in debug but if I publish it and try to connect to the server I receive a 500 error. Checking the logs the error is:

Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HM37MQFV38CV", Request id "0HM37MQFV38CV:00000003": An unhandled exception was thrown by the application.
      System.NullReferenceException: Object reference not set to an instance of an object.
         at Microsoft.Extensions.DependencyInjection.IdentityServerBuilderConfigurationExtensions.<>c.<AddSigningCredentials>b__10_2(IServiceProvider sp)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitIEnumerable(IEnumerableCallSite enumerableCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitNoCache(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
         at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
         at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
         at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
         at Microsoft.AspNetCore.Authentication.AuthenticationHttpContextExtensions.AuthenticateAsync(HttpContext context, String scheme)
         at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
         at IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.HandleException(HttpContext context, ExceptionDispatchInfo edi)
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
         at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)

Fix:

The solution is to add the following settings into appsettings.json, within the “IdentityServer” brackets. This followed the “Clients” element:

For File

 "IdentityServer": {
    "Key": {
      "Type": "File",
      "FilePath": "C:\cert.pfx",
      "Password": "password123"
    }
  }

For Development (don’t use in production obviously)

 "IdentityServer": {
    "Key": {
      "Type": "Development"
    }
  }

For Store

"IdentityServer": {
  "Key": {
    "Type": "Store",
    "StoreName": "My",
    "StoreLocation": "CurrentUser",
    "Name": "CN=MyApplication"
  }
}

Creating a Self-Signed Certificate

Created a self-signed one, add pfx file to build folder, and added its path to the appsettings.json.

Generate .pfx

You can do this via openssl:

Install openssl package (if you are using Windows, download binaries here).
Generate private key: openssl genrsa 2048 > private.pem
Generate the self signed certificate: openssl req -x509 -days 1000 -new -key private.pem -out public.pem
If needed, create PFX: openssl pkcs12 -export -in public.pem -inkey private.pem -out mycert.pfx

appsettings.json:

"IdentityServer": {
    //[...]

    "Key": {
      "Type": "File",
      "FilePath": "mycert.pfx",
      "Password": "xxxxxx"
    }
  }

Sources:

https://stackoverflow.com/questions/57012001/invalidoperationexception-key-type-not-specified-microsoft-aspnetcore-apiautho

https://github.com/jasontaylordev/CleanArchitecture/issues/80

https://stackoverflow.com/questions/64186403/blazor-web-assembly-app-net-core-hosted-publish-runtime-error

https://stackoverflow.com/questions/56094788/identityserver4-not-working-in-production

Blazor: Using a Self-Signed Certificate for IdentityServer4 in Azure App Service