Error 21916587: Missing name in the variation specifics or variation specifics set.

The NameValueList containers under the VariationSpecificsSet containers show the full list of variation specific (aka pivoting aspects) values available. For example, if each variation in this listing varied by color and size, all available colors and all available sizes would be specified in separate NameValueList containers. All of the variations defined under each Variations.Variation container should have 'Color' and 'Size' defined as values in a VariationSpecifics.NameValueList container. Please review the schema and correct any discrepancies.