There is a weird situation, hopefully someone know the reason and can help. Below is the detail.

1. I created a development site with the name of dnndev.me , DB is SQL server 2012 express, web server and DB are in the same computer, web server OS is windows server 2012. I use DNN8.01 platform. I use VS2015 to create MVC module. everything works fine in this site. We can create module, install it and load it to a page.

2. Then I created a second web site in the same web server with the site name of dnndev.aa . the db for this site is different form the one of dnndev.me, but in the same DB server. I also use VS2015 to create MVC module for this site, this module can be installed successfully, but it can't be loaded into a page. it will show error as below:

Error: ATest is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Web.Mvc.Framework.ModuleDelegatingViewEngine.RunAgainstModuleViewEngines(ControllerContext controllerContext, Func`2 engineRequest) at System.Web.Mvc.ViewEngineCollection.<>c__DisplayClass6.<FindView>b__4(IViewEngine e) at System.Web.Mvc.ViewEngineCollection.Find(Func`2 lookup, Boolean trackSearchedPaths) at System.Web.Mvc.ViewEngineCollection.FindView(ControllerContext controllerContext, String viewName, String masterName) at DotNetNuke.Web.Mvc.Framework.ActionResults.DnnViewResult.ExecuteResult(ControllerContext context, TextWriter writer) at DotNetNuke.Web.Mvc.MvcHostControl.RenderModule(ModuleRequestResult moduleResult) at DotNetNuke.Web.Mvc.MvcHostControl.OnPreRender(EventArgs e) --- End of inner exception stack trace ---

anyway, for the built in modules in DNN, it is fine to load it into a page. Also, the module i created can be installed and loaded into the page in site dnndev.me.

Does anyone can help or have any suggestion?

Thanks.