Product details page error [You are trying to access item th

Hi All,

I've created a page with Product List widget. On the Single Item Settings is set Auto-generated page. When I click on an item from the list, I receive the following error:

Type : Telerik.Sitefinity.SitefinityExceptions.ItemNotFoundException, Telerik.Sitefinity, Version=8.0.5710.0, Culture=neutral, PublicKeyToken=b28c218413bdf563
Message : You are trying to access item that no longer exists. The most probable reason is that it has been deleted by another user.
Source : Unity_ILEmit_DynamicClasses
Help link :
Data : System.Collections.ListDictionaryInternal
TargetSite : Telerik.Sitefinity.Pages.Model.PageNode GetPageNode(System.Guid)
HResult : -2146233088
Stack Trace :    at DynamicModule.ns.Wrapped_OpenAccessPageProvider_f854588332dc4481893e9b33a28aed41.GetPageNode(Guid id)
   at Telerik.Sitefinity.Modules.Pages.PageManager.GetPageNode(Guid id)
   at Telerik.Sitefinity.Security.LoginUtils.GetDefaultLoginUrl()
   at Telerik.Sitefinity.Modules.Comments.Web.UI.Frontend.CommentsSubmitForm.InitializeControls(GenericContainer container)
   at Telerik.Sitefinity.Web.UI.SimpleView.CreateChildControls()
   at System.Web.UI.Control.EnsureChildControls()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Additional Info:

MachineName :
TimeStamp : 12/7/2015 11:19:43 AM
FullName : Telerik.Sitefinity.Utilities, Version=8.0.5710.0, Culture=neutral, PublicKeyToken=b28c218413bdf563
AppDomainName :
ThreadIdentity : administrator
WindowsIdentity : DEVELOPMENT\
Requested URL : localhost:62953/.../alpha-product-1

Could you please help me to solve it?

Many thanks!