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

System.ArgumentNullException: Value cannot be null.
Parameter name: source
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Co3.Kyner.Website.Integration.Repositories.PriceRepository.GetPrices(List`1 productIdsForRetrieval, String currencyCode) in C:\Git\co3.kyner\Co3.Kyner.Website.Integration\Repositories\PriceRepository.cs:line 49
at Co3.Kyner.Website.Integration.Services.PriceService.GetPrices(List`1 productNumbers, String currencyCode, String command) in C:\Git\co3.kyner\Co3.Kyner.Website.Integration\Services\PriceService.cs:line 63
at Co3.Kyner.Website.Integration.Services.PriceService.GetPrices(String productNumber, String currencyCode, String command) in C:\Git\co3.kyner\Co3.Kyner.Website.Integration\Services\PriceService.cs:line 32
at Co3.Kyner.Website.Integration.Providers.PriceProvider.FindPrice(Product product, Double quantity, String variantId, Currency currency, String unitId, User user) in C:\Git\co3.kyner\Co3.Kyner.Website.Integration\Providers\PriceProvider.cs:line 66
at Co3.Espresso.Dw.PriceProviders.EspressoDefaultPriceProvider.FindPrice(Product product, Double quantity, String variantId, Currency currency, String unitId, User user)
at Dynamicweb.Ecommerce.Prices.PriceProvider.FindPrice(PriceContext context, PriceProductSelection selection)
at Dynamicweb.Ecommerce.Prices.PriceManager.FindPriceInternal(PriceProvider provider, PriceContext context, PriceProductSelection selection, Boolean isInformative)
at Dynamicweb.Ecommerce.Prices.PriceManager.FindPrice(PriceContext context, PriceProductSelection selection, Boolean isInformative)
at Dynamicweb.Ecommerce.Prices.PriceManager.GetPrice(PriceContext context, Product product, String unitId, Int64 stockLocationId)
at Dynamicweb.Ecommerce.Frontend.Renderer.<>c__DisplayClass84_0.b__0()
at System.Lazy`1.CreateValue()
at System.Lazy`1.LazyInitValue()
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)