ASP.NET unhandled exception has occurred. Users reporting slow response

Hi All

This is my first post so please go easy on me :-)

We have users in our organization who use Dynamics CRM for customer relation queries, there is some custom development on top of this to tailor CRM to our business requirements.

The system has been in place for approx. 10 months and the environment is setup within our VMware environment with a front end, back end with email router and dedicated SQL database server based on Windows 2008 R2 and SQL 2008 R2 standard. All speced based on the recommendations from the Microsoft CRM planning Guide.

Users are reporting occasional slowdown issues with CRM when performing tasks such as mail merge, accessing records, normally its instant but on some occasions it can take minutes to load certain areas of CRM or on rare times it fails to load at all and you just get the circular loading icon.

While troubleshooting I have noticed some ASP.Net 4.0.303.19.0 Event ID 1309 errors.

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 10/03/2015 12:42:38
Event time (UTC): 10/03/2015 12:42:38
Event ID: af62043b515844de8ce608118171e695
Event sequence: 137108
Event occurrence: 1408
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/1/ROOT-1-130703726725507288
    Trust level: Full
    Application Virtual Path: /
    Application Path: E:\Program Files\Microsoft Dynamics CRM\CRMWeb\
    Machine name: CRMSERVERFE01
 
Process information:
    Process ID: 11856
    Process name: w3wp.exe
    Account name: DOMAIN\CRMAPP_AS
 
Exception information:
    Exception type: CrmException
    Exception message: INVALID_WRPC_TOKEN
   at Microsoft.Crm.Application.Security.WrpcContext.ValidateTokenState()
   at Microsoft.Crm.Common.Application.Pages.Activities.ActivityAttachmentDownload.ConfigurePage()
   at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

 
 
Request information:
    Request URL: http://*****/****/Activities/Attachment/download.aspx?AttachmentType=1001&AttachmentId=0908c230-45c2-e411-9265-0050568f6584
    Request path: /****/Activities/Attachment/download.aspx
    User host address: 10.1.0.1
    User: DOMAIN\UserName
    Is authenticated: True
    Authentication Type: NTLM
    Thread account name: DOMAIN\CRMAPP_AS
 
Thread information:
    Thread ID: 76
    Thread account name: DOMAIN\CRMAPP_AS
    Is impersonating: False
    Stack trace:    at Microsoft.Crm.Application.Security.WrpcContext.ValidateTokenState()
   at Microsoft.Crm.Common.Application.Pages.Activities.ActivityAttachmentDownload.ConfigurePage()
   at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 
 
Custom event details:

Any ideas what could be causing this?

Thanks