When customer is trying to download the file, we are getting an error. The dev console shows this error. 
"Access to fetch at 'https://api.box.com/2.0/files/1343371417993?fields=download_url' from origin 'https:///ourdomain].com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled."

The customer can access other files.