System.NullReferenceException: Object reference not set to an instance of an object.
   at Umbraco.Core.Models.PublishedContent.PublishedContentType..ctor(IContentTypeComposition contentType, IPublishedContentTypeFactory factory) in D:\a\1\s\src\Umbraco.Core\Models\PublishedContent\PublishedContentType.cs:line 25
   at Our.Umbraco.DocTypeGridEditor.Helpers.DocTypeGridEditorHelper.<>c__DisplayClass3_0.<GetContentTypesByAlias>b__0()
   at Umbraco.Core.Cache.AppCacheExtensions.<>c__DisplayClass5_0`1.<GetCacheItem>b__0() in D:\a\1\s\src\Umbraco.Core\Cache\AppCacheExtensions.cs:line 62
   at Umbraco.Core.Cache.FastDictionaryAppCacheBase.<>c__DisplayClass21_0.<GetSafeLazy>b__0() in D:\a\1\s\src\Umbraco.Core\Cache\FastDictionaryAppCacheBase.cs:line 285
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Umbraco.Core.Cache.WebCachingAppCache.GetInternal(String key, Func`1 factory, Nullable`1 timeout, Boolean isSliding, CacheItemPriority priority, CacheItemRemovedCallback removedCallback, String[] dependentFiles) in D:\a\1\s\src\Umbraco.Core\Cache\WebCachingAppCache.cs:line 190
   at Umbraco.Core.Cache.WebCachingAppCache.Get(String key, Func`1 factory) in D:\a\1\s\src\Umbraco.Core\Cache\WebCachingAppCache.cs:line 35
   at Umbraco.Core.Cache.DeepCloneAppCache.Get(String key, Func`1 factory)
   at Umbraco.Core.Cache.AppCacheExtensions.GetCacheItem[T](IAppCache provider, String cacheKey, Func`1 getCacheItem) in D:\a\1\s\src\Umbraco.Core\Cache\AppCacheExtensions.cs:line 62
   at Our.Umbraco.DocTypeGridEditor.Helpers.DocTypeGridEditorHelper.GetContentTypesByAlias(String contentTypeAlias)
   at Our.Umbraco.DocTypeGridEditor.Helpers.DocTypeGridEditorHelper.ConvertValue(String id, String contentTypeAlias, String dataJson)
   at Umbraco.Core.Cache.AppCacheExtensions.<>c__DisplayClass5_0`1.<GetCacheItem>b__0() in D:\a\1\s\src\Umbraco.Core\Cache\AppCacheExtensions.cs:line 62
   at Umbraco.Core.Cache.FastDictionaryAppCacheBase.<>c__DisplayClass21_0.<GetSafeLazy>b__0() in D:\a\1\s\src\Umbraco.Core\Cache\FastDictionaryAppCacheBase.cs:line 285
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Umbraco.Core.Cache.HttpRequestAppCache.Get(String key, Func`1 factory) in D:\a\1\s\src\Umbraco.Core\Cache\HttpRequestAppCache.cs:line 81
   at Umbraco.Core.Cache.AppCacheExtensions.GetCacheItem[T](IAppCache provider, String cacheKey, Func`1 getCacheItem) in D:\a\1\s\src\Umbraco.Core\Cache\AppCacheExtensions.cs:line 62
   at ASP._Page_app_plugins_doctypegrideditor_render_DocTypeGridEditor_cshtml.Execute() in D:\Websites\www.inholland.nl\app_plugins\doctypegrideditor\render\DocTypeGridEditor.cshtml:line 26
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   at Umbraco.Web.Mvc.ProfilingView.Render(ViewContext viewContext, TextWriter writer) in D:\a\1\s\src\Umbraco.Web\Mvc\ProfilingView.cs:line 25
   at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)
   at ASP._Page_Views_Partials_grid_editors_Inh_Base_cshtml.Execute() in D:\Websites\www.inholland.nl\Views\Partials\grid\editors\Inh-Base.cshtml:line 21