System.ArgumentNullException: Value cannot be null.
Parameter name: source
   at System.Linq.Enumerable.Contains[TSource](IEnumerable`1 source, TSource value, IEqualityComparer`1 comparer)
   at Dynamicweb.Content.Caching.Storage.Contains(String key)
   at Dynamicweb.eCommerce.Products.Categories.Category.get_CachedCategories()
   at Dynamicweb.eCommerce.Products.Categories.Category.GetCategoryByID(String categoryID, String languageID)
   at Dynamicweb.eCommerce.Products.Categories.Field.CachedFields()
   at Dynamicweb.eCommerce.Products.Categories.Field.GetFieldsByCategoryId(String categoryId, String languageId)
   at Dynamicweb.eCommerce.Products.Product.GetCategoryValue(String categoryID, String fieldID, Boolean includeInheritance)
   at Co3.Espresso.Dw8.Extenders.Products.ProductConfiguratorExtender.GetCategoryValue(Product product, String sysName) in c:\Data\Development\git\espresso-solution\Co3.Espresso.Dynamicweb8\Extenders\Products\ProductConfiguratorExtender.cs:line 135
   at Co3.Espresso.Dw8.Extenders.Products.ProductConfiguratorExtender.GenerateSectionsData(ProductConfigurationEntity& pce, Template& template, Product product) in c:\Data\Development\git\espresso-solution\Co3.Espresso.Dynamicweb8\Extenders\Products\ProductConfiguratorExtender.cs:line 31
   at Co3.Espresso.Dw8.Extenders.Products.ProductConfiguratorExtender.ExtendTemplate(Template template, ProductTemplateExtender extender, CacheEngine cacheEngine) in c:\Data\Development\git\espresso-solution\Co3.Espresso.Dynamicweb8\Extenders\Products\ProductConfiguratorExtender.cs:line 170
   at Co3.Espresso.Dw8.Extenders.ProductExtender.ExtendTemplate(Template template) in c:\Data\Development\git\espresso-solution\Co3.Espresso.Dynamicweb8\Extenders\ProductExtender.cs:line 97
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProductTemplateExtenders(Product Product, Template Template, Boolean ExtendedProperties)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProduct(Product Product, Boolean ExtendedProperties, Template Template, Int32 loopCounter, Boolean renderRelated, String productURL, Int32 quantity, Int32 wishListID, Boolean renderPublicList, Int32 orderLineOfProductCount)
   at Dynamicweb.eCommerce.Frontend.Renderer.RenderProduct(Product Product, Boolean ExtendedProperties)
   at Dynamicweb.eCommerce.Frontend.Frontend.EcomRender()
   at Dynamicweb.eCommerce.Frontend.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModule(DataRow& ParagraphRow)