Error 107: The category is not valid, select another category.

Please check the PrimaryCategory.CategoryID field to verify if you are using a valid eBay leaf category ID. You can use the getCategoryTree or getCategorySubtree methods to get valid leaf category IDs. In the responses of these methods, a leafCategoryTreeNode boolean with a value of true will indicate leaf categories. Another possible scenario that may trigger this error is if a deprecated category ID is used, and the CategoryMappingAllowed field is included in the request and set to false (default value of this setting is true). The GetCategoryMappings call can be used to see which category IDs are deprecated, and the replacement category IDs that should be used instead.