Symptoms

Getting an error while opening designer
 

Diagnoses

We tried upgrading from 4.6.7 to 4.6.9. K2 designer does not open up. Using own company cert instead K2 self-signed cert for WindowsSTS.

Gives an error:
Event code: 3003
Event message: A validation error has occurred.
Event time: 4/16/2015 8:10:52 AM
Event time (UTC): 4/16/2015 3:10:52 PM
Event ID: 6774ac90727c47beaf3ff4ee003f734a
Event sequence: 6
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/1/ROOT/Identity/STS/Windows-2-130736706493307487
Trust level: Full
Application Virtual Path: /Identity/STS/Windows
Application Path: D:Program Files (x86)K2 blackpearlWebServicesIdentitySTSWindows
Machine name: DLX

Process information:
Process ID: 10852
Process name: w3wp.exe
Account name: DENALLIXK2Service

Exception information:
Exception type: HttpRequestValidationException
Exception message: A potentially dangerous Request.QueryString value was detected from the client (Error="...ation see at System.Web.HttpRequest.ValidateString(String value, String collectionKey, RequestValidationSource requestCollection)
at System.Web.HttpValueCollection.GetValues(String name)
at System.Web.Mvc.NameValueCollectionValueProvider.ValueProviderResultPlaceholder.GetResultFromCollection(String key, NameValueCollection collection, CultureInfo culture)
at System.Lazy`1.CreateValue()
at System.Lazy`1.LazyInitValue()
at System.Web.Mvc.NameValueCollectionValueProvider.ValueProviderResultPlaceholder.get_ValidatedResult()
at System.Web.Mvc.NameValueCollectionValueProvider.GetValue(String key, Boolean skipValidation)
at System.Web.Mvc.ValueProviderCollection.<>c__DisplayClass9.b__4(IValueProvider provider)
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
at System.Linq.Enumerable.FirstOrDefaultlTSource](IEnumerable`1 source)
at System.Web.Mvc.DefaultModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
at System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor)
at System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.b__1e(AsyncCallback asyncCallback, Object asyncState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.BeginiTResult](AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.BeginiTResult](AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag)
at System.Web.Mvc.Controller.<>c__DisplayClass1d.b__17(AsyncCallback asyncCallback, Object asyncState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.BeginiTResult](AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag, Int32 timeout)
at System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.BeginiTResult](AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate endDelegate, Object tag)
at System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.b__2(AsyncCallback asyncCallback, Object asyncState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.BeginiTResult](AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate`1 endDelegate, Object tag, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object state, BeginInvokeDelegate beginDelegate, EndInvokeDelegate endDelegate, Object tag)
at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.
 

Resolution

We found hidden special characters in the front of the thumbprint in the web.config file for the Windows STS web application. It is hidden when the encoding is UTF-8 (which is usually the default) vs when the encoding is ANSI.

Please install Notepad (another text editor tool) and to check if the thumbprint in the Windows STS web.config file contain any special characters. Perhaps also copy the Thumbprint in the Issuers table from the database into notepad with the ANSI encoding to see if any special characters are present.