Hi everyone, we have an Epi site with CMS 11.15.0 and Commerce 13.18.2, hosted in an Azure appservice. It is registering a lot of exceptions in Azure Insights, and we just don't know where are those coming from. The ones with most occurrences and with no easy explanation are:
1. CheckVirtualFileExists
This one happens on every .aspx request that does not exist. We use the 404 Geta handler, and it redirects to our "not found page" correctly, but it logs a lot of these exceptions in azure.
System.Web.HttpException:
at System.Web.UI.Util.CheckVirtualFileExists (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.UI.PageHandlerFactory.GetHandlerHelper (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.UI.PageHandlerFactory.GetHandler (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+<>c__DisplayClass285_0.<ExecuteStepImpl>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker.Invoke (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker+<>c__DisplayClass4_0.<Invoke>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at Microsoft.AspNet.TelemetryCorrelation.TelemetryCorrelationHttpModule.OnExecuteRequestStep (Microsoft.AspNet.TelemetryCorrelation, Version=1.0.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35)
at System.Web.HttpApplication+<>c__DisplayClass284_0.<OnExecuteRequestStep>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker.Invoke (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication.ExecuteStepImpl (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication.ExecuteStep (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
From the IIS logs on azure:
2020-07-20 22:23:38 AZAPP-NXS-EPI-CMS-PREP-01__E284 GET /search.aspx 404;https://azapp-nxs-epi-cms-prep-01__e284:80/search.aspx?page=11&category=953&X-ARR-LOG-ID=77c41081-2434-4707-a9e4-966b3c94b9c3 443
Testing the same url, but in my local environment (note no 404):
2020-07-20 23:13:43 127.0.0.1 GET /search.aspx page=11&category=953 80 - 127.0.0.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/83.0.4103.116+Safari/537.36 - 200 0 0 1141
2. Server cannot append header after HTTP headers have been sent.
System.Web.HttpException:
at System.Web.HttpResponse.AppendHeader (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpResponseWrapper.AppendHeader (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at EPiServer.Web.MediaHandlerBase.CheckIsModifiedAndAddETag (EPiServer.Framework.AspNet, Version=11.15.0.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7)
at EPiServer.Web.MediaHandlerBase.NotModifiedHandling (EPiServer.Framework.AspNet, Version=11.15.0.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7)
at EPiServer.Web.BlobHttpHandler.ProccessBlobRequest (EPiServer.Cms.AspNet, Version=11.15.0.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7)
at EPiServer.Web.BlobHttpHandler.ProcessRequestAsyncInternal (EPiServer.Cms.AspNet, Version=11.15.0.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7)
at EPiServer.Web.BlobHttpHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest (EPiServer.Cms.AspNet, Version=11.15.0.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7)
at System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+<>c__DisplayClass285_0.<ExecuteStepImpl>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker.Invoke (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker+<>c__DisplayClass4_0.<Invoke>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at Microsoft.AspNet.TelemetryCorrelation.TelemetryCorrelationHttpModule.OnExecuteRequestStep (Microsoft.AspNet.TelemetryCorrelation, Version=1.0.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35)
at System.Web.HttpApplication+<>c__DisplayClass284_0.<OnExecuteRequestStep>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication+StepInvoker.Invoke (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication.ExecuteStepImpl (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
at System.Web.HttpApplication.ExecuteStep (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
This one is the most random exception. Happens a lot when trying to access to images. I had a chat with Epi Support, they asked me to review my redirects, which I did and error is still happening. This can't be reproduced in my local environment either.
These two exceptions happen a lot during the day, this is just a report from the past 6 hours:
![]()
Hope any of you have seen this before and have some insight on to what might be happening. We use azure deployment slots to decrease downtime, not sure if that can be an issue.
Thanks!