Error

Using a service from a federated ArcGIS Enterprise Portal/ArcGIS Server in a web map connected to the ArcGIS Experience Builder Map widget in ArcGIS Online will throw a 'Access to fetch at '<service url>' from origin 'https://experience.arcgis.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource' Console error.