Lost uCommerce interface within Sitecore

Question

I am developing a web application using SiteCore 8 and uCommerce. To configure uCommerce I go through Sitecore and load the uCommerce interface. This morning I tried to load the uCommerce interface in the normal way, i.e logged into Sitecore and loaded uCommerce, but got nothing more than a white screen in Sitecore. Looking at the browser console I can see 2 different 500 errors:

Failed to load resource: the server responded with a status of 500 (Internal Server Error) http://local.myapp.co.uk/ucommerceapi/Content/undefined/RootNode Failed to load resource: the server responded with a status of 500 (Internal Server Error) http://local.myapp.co.uk/ucommerceapi/Localization/TranslatedStrings Failed to load resource: the server responded with a status of 500 (Internal Server Error) http://local.myapp.co.uk/ucommerceapi/Content/tree/RootNode Failed to load resource: the server responded with a status of 500 (Internal Server Error)

If I click on the url in the error I get a page that displays:

Server Error in '/' Application.

Value cannot be null. Parameter name: EndpointHost.Config

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null. Parameter name: EndpointHost.Config

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentNullException: Value cannot be null. Parameter name: EndpointHost.Config]

[ConfigurationErrorsException: ServiceStack: AppHost does not exist or has not been initialized. Make sure you have created an AppHost and started it with 'new AppHost().Init();' in your Global.asax Application_Start()]
ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory..cctor() +836

[TypeInitializationException: The type initializer for 'ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory' threw an exception.]
ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory..ctor() +0

[TargetInvocationException: Exception has been thrown by the target of an invocation.] System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +159
System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +256 System.Activator.CreateInstance(Type type, Boolean nonPublic) +127 System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark) +14297981
System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +198 System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) +28
System.Web.HttpRuntime.CreateNonPublicInstance(Type type, Object[] args) +83 System.Web.Configuration.HandlerFactoryCache..ctor(String type) +57 System.Web.HttpApplication.GetFactory(String type) +94
System.Web.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +375 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +288

I have tried recreating the Global.asax, I have tried replacing all the sitecore folders:

1. sitecore
2. sitecore modules

3. sitecore_files

   and the App_Config folder using files from a colleagues machine that is working fine but not luck. I can copy my colleagues solution to my PC and it works fine (except he has none of the work I have done)

Can anyone throw any light on what the problem might be?

Answer 1

In case anyone else stumbles on this problem. I deleted the website from IIS then recreated it and the problem has gone away. I have no idea why this has fixed the issue, as I have changed nothing in IIS for days.