Calling servicenow endpoint from postman failing

[adakshi]

Hitting servicenow endpoint from postman failing with error - 

Error: getaddrinfo ENOTFOUND goldmanirmdemo.service-now.com

This is using both basic authentication and OAuth , also followed the steps mentioned here - https://www.servicenow.com/community/developer-blog/oauth-2-0-with-inbound-rest/ba-p/2278926 but still stuck with same error.