Hi Bruce,
Can you be more specific? I think you mean https://blogs.bing.com/maps/2019-05/bing-maps-multi-itinerary-optimization-api-launches-today and https://www.microsoft.com/en-us/maps/multi-itinerary-optimization. Note that under a Basic key and Basic free account the API is limited to three drivers and twenty locations as documented.
Please see https://learn.microsoft.com/en-us/bingmaps/rest-services/routes/optimized-itinerary -> API Limits
Sincerely,
IoTGirl