The referenced OpenAccessContext or 'IObjectScope' i

I am doing some background thread task in sitefinity. previously i was getting exception at the line.

 Config.Get<DataConfig>().ConnectionStrings. To overcome it i have sent dummy ashx request to my site and able to get connection string and connect ot db.

Now when trying to access DynamicContent via code

DynamicModuleManager dynamicModuleManager = DynamicModuleManager.GetManager();
            Type itemType = TypeResolutionService.ResolveType(key);
            DynamicContent item = dynamicModuleManager.GetDataItem(itemType, id);

            return item;

I am getting above mentioned error.

Any idea how to overcome this The referenced OpenAccessContext or 'IObjectScope' is already closed (UnsynchronizedPMProxy). error?