Hi

I have ASP classic site that stopped working! I did not make any changes. It works for a few minutes after recycle pool. 
Direct URL work - f.x  www.xxx.dk/login/login.asp works but notwww.xxx.dk/login/

This is the error:

Server Error in '/' Application.

Object reference not set to an instance of an object.

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.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 

Stack Trace: 

[NullReferenceException: Object reference not set to an instance of an object.]
   System.Web.HttpApplication.GetNotifcationContextProperties(Boolean& isReentry, Int32& eventCount) +106
   System.Web.PipelineStepManager.ResumeSteps(Exception error) +145
   System.Web.HttpApplication.ResumeSteps(Exception error) +13
   System.Web.HttpApplication.BeginProcessRequestNotification(HttpContext context, AsyncCallback cb) +86
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +360

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3429.0

Any ideas?

UPDATE: Changing from Integrated Pool to Classic seems to have fixed it. But I would still like to find the underlaying error.