I am monitoring our Microsoft Remote Desktop Gateway website using an HTTP sensor. Whenever the sensor trigger, the server logs a warning event, ID 1309. The sensor is using GET, and is not inheriting SNI. Not sure if my sensor needs adjusting. Event log entry follows...any ideas?

Log Name:      Application
Source:        ASP.NET 4.0.30319.0
Date:          2/6/2019 2:34:33 PM
Event ID:      1309
Task Category: Web Event
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      <hostname redacted>
Description:
Event code: 3005 
Event message: An unhandled exception has occurred. 
Event time: 2/6/2019 2:34:33 PM 
Event time (UTC): 2/6/2019 10:34:33 PM 
Event ID: 47a37f7c251f4a20b35e6e079ea8d8e5 
Event sequence: 18775 
Event occurrence: 2575 
Event detail code: 0 
 
Application information: 
    Application domain: /LM/W3SVC/1/ROOT/RDWeb/Pages-1-131918875365100057 
    Trust level: Full 
    Application Virtual Path: /RDWeb/Pages 
    Application Path: C:\Windows\Web\RDWeb\Pages\ 
    Machine name: ********
 
Process information: 
    Process ID: 2044 
    Process name: w3wp.exe 
    Account name: IIS APPPOOL\RDWebAccess 
 
Exception information: 
    Exception type: NullReferenceException 
    Exception message: Object reference not set to an instance of an object.
   at Microsoft.TerminalServices.Publishing.Portal.FormAuthentication.TSFormAuthTicketInfo..ctor(HttpContext objHttpContext)
   at ASP.en_us_default_aspx.<GetAppsAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.UI.PageAsyncTaskManager.<ExecuteTasksAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.UI.Page.<ProcessRequestAsync>d__554.MoveNext()

 
 
Request information: 
    Request URL: https://<hostname redacted>:443/RDWeb/Pages/en-US/Default.aspx 
    Request path: /RDWeb/Pages/en-US/Default.aspx 
    User host address: <IP address of PRTG monitor>
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: IIS APPPOOL\RDWebAccess 
 
Thread information: 
    Thread ID: 65 
    Thread account name: IIS APPPOOL\RDWebAccess 
    Is impersonating: False 
    Stack trace:    at Microsoft.TerminalServices.Publishing.Portal.FormAuthentication.TSFormAuthTicketInfo..ctor(HttpContext objHttpContext)
   at ASP.en_us_default_aspx.<GetAppsAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.UI.PageAsyncTaskManager.<ExecuteTasksAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.UI.Page.<ProcessRequestAsync>d__554.MoveNext()

Article Comments

Attention: This article is a record of a conversation with the Paessler support team. The information in this conversation is not updated to preserve the historical record. As a result, some of the information or recommendations in this conversation might be out of date.

Are you just calling the URL of the page (i.e. the login form) or do you provide it with any POST data for authentication purposes?

PRTG Scheduler | PRTGapi | Feature Requests | WMI Issues | SNMP Issues

Kind regards,
Stephan Linke, Tech Support Team


Feb, 2019 - Permalink

The former, since I am not familiar with what data would be sent in a POST. Is that likely causing the warning? If so, I can research what to use in a POST request.


Feb, 2019 - Permalink

I figured it out! It wasn't the sensor settings at all. The system time on the webserver was off by about a minute. Once I changed the time source so that NTP worked properly, these warnings went away.


Feb, 2019 - Permalink

Hi Jeff,

Thanks for the update, glad it's up and running now.

PRTG Scheduler | PRTGapi | Feature Requests | WMI Issues | SNMP Issues

Kind regards,
Stephan Linke, Tech Support Team


Feb, 2019 - Permalink