In Salesforce, add the origin serving the code to a CORS whitelist. If a browser that supports CORS makes a request to an origin in the whitelist.
Salesforce returns the origin in the Access-Control-Allow-Origin HTTP header, along with any additional CORS HTTP headers.
If the origin is not included in the whitelist, Salesforce returns HTTP status code 403.
To configure it follow the below steps,
- From Setup, enter CORS in the Quick Find box, then select CORS.
- Select New.
- Enter an origin URL pattern.
The origin URL pattern must include the HTTPS protocol (unless you’re using your localhost) and a domain name and can include a port. The wildcard character (*) is supported and must be in front of a second-level domain name. For example, https://*.example.com adds all subdomains of example.com to the whitelist.The origin URL pattern can be an IP address. However, an IP address and a domain that resolve to the same address are not the same origin, and you must add them to the CORS whitelist as separate entries.