An error occurred while attaching module (Dynamicweb.Frontend.Content)

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.ThrowHelper.ThrowKeyNotFoundException()
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Dynamicweb.Ecommerce.Products.GroupRelation.GetGroupRelationsByChildId(String childId)
   at Dynamicweb.Ecommerce.ProductCategoryFieldService.GetCategoriesFromGroups(List`1 categories, HashSet`1& idsHash, IEnumerable`1 groups, Int32 currentLevel, Int32 minLevel, Nullable`1 maxLevel)
   at Dynamicweb.Ecommerce.ProductCategoryFieldService.GetInheritedCategories(IEnumerable`1 groups, Boolean includeProductProperties)
   at Dynamicweb.Ecommerce.Frontend.Renderer.RenderProductCategories(Product product, Template template, String loopName, Lazy`1 categoryFieldSortings, RenderingContext renderingContext)
   at Dynamicweb.Ecommerce.Frontend.Renderer.RenderProduct(Product product, Boolean extendedProperties, Template template, Int32 loopCounter, Boolean renderRelated, String productUrl, Int32 quantity, Int32 wishListId, Boolean renderPublicList, Boolean isRecursiveCall, Lazy`1 categoryFieldSorting, Int32 orderLineOfProductCount, RenderingContext renderingContext, String unitId)
   at Dynamicweb.Ecommerce.Frontend.Renderer.RenderVariantCombinations(Product product, String unitId, Template parentTemplate, String loopName, Lazy`1 categoryFieldSortings, RenderingContext renderingContext)
   at Dynamicweb.Ecommerce.Frontend.Renderer.RenderProduct(Product product, Boolean extendedProperties, Template template, Int32 loopCounter, Boolean renderRelated, String productUrl, Int32 quantity, Int32 wishListId, Boolean renderPublicList, Boolean isRecursiveCall, Lazy`1 categoryFieldSorting, Int32 orderLineOfProductCount, RenderingContext renderingContext, String unitId)
   at Dynamicweb.Ecommerce.Frontend.Renderer.RenderProduct(Product product, Boolean extendedProperties, String unitId)
   at Dynamicweb.Ecommerce.Frontend.Frontend.EcomRender()
   at Dynamicweb.Ecommerce.Frontend.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)