Hi Scott,
Have you written an App or are you talking about the Bing.com/maps website?
The CORS issue is usually because you are trying to access a service that is on a different domain. If you trace the error, do you find a domain mismatch? If you call https://sdk,virtualearth.net/api/maps/mapcontrol as documented at https://learn.microsoft.com/en-us/bingmaps/v8-web-control/creating-and-hosting-map-controls/creating-a-basic-map-control does the issue resolve?
Sincerely,
IoTGirl