Server Error in '/' Application.

Sequence contains no elements

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Sequence contains no elements

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[InvalidOperationException: Sequence contains no elements]
   System.Linq.Enumerable.First(IEnumerable`1 source) +335
   Umbraco.Core.Configuration.UmbracoSettings.ContentErrorsElement.get_Error404Collection() +85
   Umbraco.Core.Configuration.UmbracoSettings.ContentElement.get_Error404Collection() +17
   Umbraco.Web.Routing.ContentFinderByLegacy404.TryFindContent(PublishedContentRequest pcr) +98
   Umbraco.Web.Routing.ContentLastChanceFinderByNotFoundHandlers.HandlePageNotFound(PublishedContentRequest docRequest) +473
   Umbraco.Web.Routing.ContentLastChanceFinderByNotFoundHandlers.TryFindContent(PublishedContentRequest docRequest) +10
   Umbraco.Web.Routing.PublishedContentRequestEngine.HandlePublishedContent() +529
   Umbraco.Web.Routing.PublishedContentRequestEngine.FindPublishedContentAndTemplate() +250
   Umbraco.Web.Routing.PublishedContentRequestEngine.PrepareRequest() +107
   Umbraco.Web.UmbracoModule.ProcessRequest(HttpContextBase httpContext) +361
   Umbraco.Web.UmbracoModule.<Init>b__8(Object sender, EventArgs e) +80
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +144
   System.Web.<>c__DisplayClass285_0.<ExecuteStepImpl>b__0() +26
   System.Web.StepInvoker.Invoke(Action executionStep) +107
   System.Web.<>c__DisplayClass4_0.<Invoke>b__0() +23
   Microsoft.AspNet.TelemetryCorrelation.TelemetryCorrelationHttpModule.OnExecuteRequestStep(HttpContextBase context, Action step) +64
   System.Web.<>c__DisplayClass284_0.<OnExecuteRequestStep>b__0(Action nextStepAction) +56
   System.Web.StepInvoker.Invoke(Action executionStep) +91
   System.Web.<>c__DisplayClass4_0.<Invoke>b__0() +23
   Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule.OnExecuteRequestStep(HttpContextBase context, Action step) +124
   System.Web.<>c__DisplayClass284_0.<OnExecuteRequestStep>b__0(Action nextStepAction) +56
   System.Web.StepInvoker.Invoke(Action executionStep) +91
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +9958594
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +73


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4690.0