Sitecore 9.1.1 null exception on EnsureLoggedInForPreview.Process(PipelineArgs args)

Question

I have got Sitecore 9.1.1 installed on CM and CD server. I am getting the below exception only on the CD server:

5048 12:18:51 ERROR Application error.
Exception: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: Sitecore.Mvc
   at Sitecore.Mvc.Pipelines.Request.RequestBegin.EnsureLoggedInForPreview.Process(PipelineArgs args)
   at (Object , Object )
   at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain, Boolean failIfNotExists)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain)
   at Sitecore.Mvc.Pipelines.PipelineService.RunPipeline[TArgs](String pipelineName, TArgs args)
   at Sitecore.Mvc.Routing.RouteHttpHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I did have a look at the process in Sitecore.Mvc it is:

public class EnsureLoggedInForPreview
  {
    public void Process(PipelineArgs args)
    {
      if (Context.PageMode.get_IsNormal() || Context.get_IsLoggedIn())
        return;
      using (new SiteContextSwitcher(Factory.GetSite("shell")))
      {
        using (new UserSwitcher(Context.get_User()))
          ShellPage.IsLoggedIn();
      }
    }

I am imagining the page mode is not available on CD server. Should I disable the pipeline on the CD server?

Answer 1

I manage to fix the problem my contact Sitecore support. There was a problem with order of my custom register routes pipeline was running in the pipeline. I had to change all my custom route piplelines as below:

From:
<processor patch:before="processor[@type='Sitecore.Mvc.Pipelines.Loader.InitializeGlobalFilters, Sitecore.Mvc']"            type="Sitecore.Feature.Integeration.Infrastructure.Pipelines.RegisterRoutes, Sitecore.Feature.BPointIntgration" />

To:

<processor patch:after="processor[@type='Sitecore.Mvc.Pipelines.Loader.InitializeRoutes, Sitecore.Mvc']"            type="Sitecore.Feature.Integeration.Infrastructure.Pipelines.RegisterRoutes, Sitecore.Feature.BPointIntgration" />

Answer 2

This looks like the version of some dlls is not correct.

Please check the version of Sitecore.mvc.dll and other dlls as well.