Could not find an IRouter associated with the ActionContext

[Misha3739]

Hello, my friends! We have a .Net Core MVC project with Razor Pages already working on version 2.2 for years. We use Scaffolded Identity Pages generated long time ago and everything works fine. We are trying to update to .Net Core 3.1. After fixing package versions and compatibility issues, we got stuck with (this is the part of Startup.cs class):

app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints => {
                    endpoints.MapControllerRoute(
                        name: "default",
                        pattern: "{controller=Home}/{action=Index}/{id?}");
                    //For identity
                    endpoints.MapRazorPages();  //this line causes issue
                });

If we don't use endpoints.MapRazorPages(), the Identity pages are not being found by application, but Controllers not marked with [Authorize] attributes are fine available. If use endpoints.MapRazorPages(), we are able to Login , navigate to default Home/Index URL and Auth Middleware is working fine, but we got this issue trying to navigate to any other page via Menu or typing url: System.InvalidOperationException: Could not find an IRouter associated with the ActionContext. If your application is using endpoint routing then you can get a IUrlHelperFactory with dependency injection and use it to create a UrlHelper, or use Microsoft.AspNetCore.Routing.LinkGenerator. at Microsoft.AspNetCore.Mvc.Routing.UrlHelper.get_Router() at Microsoft.AspNetCore.Mvc.Routing.UrlHelper.GetVirtualPathData(String routeName, RouteValueDictionary values) at Microsoft.AspNetCore.Mvc.Routing.UrlHelper.Action(UrlActionContext actionContext) at Microsoft.AspNetCore.Mvc.UrlHelperExtensions.Action(IUrlHelper helper, String action, String controller, Object values, String protocol, String host, String fragment) at Microsoft.AspNetCore.Mvc.UrlHelperExtensions.Action(IUrlHelper helper, String action, String controller, Object values) at SmartBreadcrumbs.BreadcrumbTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output) at Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.gAwaited|0_0(Task task, TagHelperExecutionContext executionContext, Int32 i, Int32 count) at AspNetCore.Views_Home_Campaigns.ExecuteAsync() in PROJECTPATH\Views\Home\Campaigns.cshtml:line 8 at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageCoreAsync(IRazorPage page, ViewContext context) at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageAsync(IRazorPage page, ViewContext context, Boolean invokeViewStarts) at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderAsync(ViewContext context) at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable1 statusCode) at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable1 statusCode) at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ActionContext actionContext, IView view, ViewDataDictionary viewData, ITempDataDictionary tempData, String contentType, Nullable`1 statusCode) at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewResultExecutor.ExecuteAsync(ActionContext context, ViewResult result) at Microsoft.AspNetCore.Mvc.ViewResult.ExecuteResultAsync(ActionContext context) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|29_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters() --- End of stack trace from previous location where exception was thrown --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.gAwaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.gAwaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker invoker) at Microsoft.AspNetCore.Routing.EndpointMiddleware.gAwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger) at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)

Why is this issue occurred and how can we find workaround? We didn't change any of Controllers or Views signature and cannot understand why Routing is not working from the box....

[javiercn]

@Misha3739 thanks for contacting us.

I think that the issue might be caused by this tag helper.

at Microsoft.AspNetCore.Mvc.UrlHelperExtensions.Action(IUrlHelper helper, String action, String controller, Object values, String protocol, String host, String fragment)
at Microsoft.AspNetCore.Mvc.UrlHelperExtensions.Action(IUrlHelper helper, String action, String controller, Object values)
at SmartBreadcrumbs.BreadcrumbTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output)

Are you overriding the IUrlTagHelperFactory in your app in any way?

[Misha3739]

Javier, thank you a lot for the response! We will be working to find for the solution, unfortunately the BreadCrumbs third-party library is not compatible with itself's modern versions, and we need to have time to fix upgrade issues related with BreadCrumbs and verify the solution. I didn't think this library to have such non-obvious side-effect. Anyway, you specified the way we should to work on, that's great!