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

System.ArgumentNullException: Value cannot be null.
Parameter name: pattern
   at System.Text.RegularExpressions.Regex..ctor(String pattern, RegexOptions options, TimeSpan matchTimeout, Boolean useCache)
   at System.Text.RegularExpressions.Regex..ctor(String pattern)
   at Custom.SeoProductName.CustomFieldProvider.RegexReplaceInFieldProvider.GetProductValue(Product product, Object fieldValue, String languageId, Dictionary`2 settings) in D:\a\1\s\Custom.RegularExpressionCustomProductField\CustomFieldProvider\RegexReplaceInFieldProvider.cs:line 33
   at Dynamicweb.Ecommerce.Products.ProductFieldTypeProvider.GetProductValue(Product product, FieldType fieldType, Object fieldValue)
   at Dynamicweb.Ecommerce.Products.ProductFieldValueCollection.RefreshProviderFields(Product product)
   at Dynamicweb.Ecommerce.Products.ProductRepository.ExtractProduct(IDataReader dataReader, Nullable`1& groupProductRelationSortingExists)
   at Dynamicweb.Ecommerce.Products.ProductRepository.GetProductsBySql(CommandBuilder query, Boolean doRefactoring, Boolean bulkFill, Boolean useAssortments)
   at Dynamicweb.Ecommerce.Products.ProductRepository.GetProductsByGroupIdAndSearchValue(String groupId, String topValue, String searchValue, String productVariantId, Boolean isFrontend, String productLanguageId, Boolean useAssortments)
   at Dynamicweb.Ecommerce.Frontend.Frontend.List(String groups)
   at Dynamicweb.Ecommerce.Frontend.Frontend.EcomRender()
   at Dynamicweb.Ecommerce.Frontend.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)