The site give a .NET errore after upgrade the staging site from 6.1.6 tp 6.2.0 ( + Ublogsy Pack ).

The error is:

ERROR Umbraco.Core.UmbracoApplicationBase - [Thread 23] An unhandled exception occurred
System.NullReferenceException: Object reference not set to an instance of an object.
   in uHelpsy.Extensions.IPublishedContentExtensions.GetValueFirstOf(IPublishedContent d, String[] aliases) in d:\_PROJECTS\Personal\uHelpsy - Library\uHelpsy\Source\uHelpsy.Web\Extensions\IPublishedContentExtensions.cs:riga 22
   in ASP._Page_Views_Partials_uBlogsyGlobalSeoMeta_cshtml.Execute() in c:\HostingSpaces\primaprint\demozone.econewsweb.it\wwwroot\Views\Partials\uBlogsyGlobalSeoMeta.cshtml:riga 11
   in System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   in System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   in System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   in System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance)
   in System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer)
   in Umbraco.Core.Profiling.ProfilingView.Render(ViewContext viewContext, TextWriter writer)
   in System.Web.Mvc.HtmlHelper.RenderPartialInternal(String partialViewName, ViewDataDictionary viewData, Object model, TextWriter writer, ViewEngineCollection viewEngineCollection)
   in System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)
   in System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName)
   in ASP._Page_Views_EcoMasterTemplate_cshtml.Execute() in c:\HostingSpaces\primaprint\demozone.econewsweb.it\wwwroot\Views\EcoMasterTemplate.cshtml:riga 18
   in System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   in System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   in System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   in System.Web.WebPages.WebPageBase.<>c__DisplayClass7.<RenderPageCore>b__6(TextWriter writer)
   in System.Web.WebPages.HelperResult.WriteTo(TextWriter writer)
   in System.Web.WebPages.WebPageBase.Write(HelperResult result)
   in System.Web.WebPages.WebPageBase.RenderSurrounding(String partialViewName, Action`1 body)
   in System.Web.WebPages.WebPageBase.PopContext()
   in System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   in System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance)
   in System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer)
   in Umbraco.Core.Profiling.ProfilingView.Render(ViewContext viewContext, TextWriter writer)
   in System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
   in System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
   in System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<InvokeActionResultWithFilters>b__17()
   in System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)
   in System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()
   in System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)
   in System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()
   in System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)
   in System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)
   in System.Web.Mvc.Controller.<>c__DisplayClass1d.<BeginExecuteCore>b__19()
   in System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
   in System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _)
   in System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
   in System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
   in System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
   in System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
   in System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult)
   in System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult)
   in System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult)
   in System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
   in System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
   in System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
   in System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
   in System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   in System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)