New Post: OutlookApi.NavigationModule Cast Error

I'm trying to get a ContactsModule Object from outlook but I keep getting a cast error:

NetOffice.OutlookApi.NavigationModules NavigationModules = OutlookApp.Session.GetDefaultFolder(OlDefaultFolders.olFolderContacts).GetExplorer().NavigationPane.Modules;
NetOffice.OutlookApi.ContactsModule ContactsModule = NavigationModules.GetNavigationModule(OlNavigationModuleType.olModuleContacts);

I'm completely lost on what I'm doing wrong. Any ideas?