The URL parameter "categoryId" can be used in two ways: - use the unique ID of the resource category assigned by TIMIFY ("categoryId"). In this case, you don't need the QUERY parameter "external" - use the "externalId" that you added to this resource category. In this case, you need to add the parameter "external" ( for ex.:/?external=1) so the Developer API will search by your "externalId" and not by "categoryId" assigned by TIMIFY
You can add "externalId" to the resource category with the Developer API endpoints POST /resources/categories and PATCH resources/cartegories/:categoryId