Hi

We have an internet site running DNN 7.4 on Server 2012. We have also installed the DNN AD authentication component which seems to work correctly in terms of authenticating users, however frequently, we see errors that completely shut down the worker thread.

I suspect the culprit may be the AD module, but at this stage, I'm not 100% certain as the error message is extremely low level and we don't get a reference to the actual module erroring in the stack trace.  What we do get is the following :

COMException (0x80070006): The handle is invalid. (Exception from HRESULT: 0x80070006 (E_HANDLE))]   System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo) +0   System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode) +10851991   System.Web.Hosting.IIS7WorkerRequest.ReMapHandlerAndGetHandlerTypeString(HttpContext httpContext, String path, Boolean& handlerExists) +70   System.Web.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +215   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

I've never come across this error before on any DNN installation, and the only thing out of the ordinary on it is the AD authentication module thus my suspicions that it may be at fault. Again, to be clear, the authentication does work, users are correctly authenticated against the domain, however at intermittent times, the entire WP thread errors with the preceding error as users move around the site.

Any suggestions would be greatly receive.

Regards
Stuart