I try to assign a CRM Case to someone else; then I am getting
following error message. I know sometimes these information is not
enough to get an idea about this issue. But if anyone have any
solution for this please let me know.

[ArgumentException: The parameter is incorrect.]
Microsoft.Crm.Platform.ComProxy.CRMIncidentClass.R oute(CUserAuth&
Caller, String IncidentId, String SourceQueueId, ROUTE_TYPE_CODE
RouteTypeCode, String EndPointId) +0
Microsoft.Crm.Application.Platform.Incident.Route( String
sourceQueueId, ROUTE_TYPE_CODE routeTypeCode, String endPointId) +66
Microsoft.Crm.Web.CS.CaseDetailPage.AssignToUser(O bject sender,
DataEventArgs e) +202

Microsoft.Crm.Application.Forms.DataEventProcessor .Raise(FormEventId
eventId, FormState state, User user, String objectId, Entity entity)
+176
Microsoft.Crm.Application.Forms.AppForm.RaiseDataE vent(FormEventId
eventId) +89
Microsoft.Crm.Application.Forms.EndUserForm.Initia lize(Entity
entity) +56
Microsoft.Crm.Application.Forms.CustomizableForm.E xecute(Entity
entity, String formId, String formType) +83
Microsoft.Crm.Application.Forms.CustomizableForm.E xecute(Entity
entity) +13
Microsoft.Crm.Web.CS.CaseDetailPage.ConfigureForm( ) +306
Microsoft.Crm.Application.Controls.AppPage.OnPreRe nder(EventArgs e)
+30
System.Web.UI.Control.PreRenderRecursiveInternal() +62
System.Web.UI.Page.ProcessRequestMain() +1499