REST API 401 User Not Authorized

I have been able to connect to my SEPM API using Postman, however when I try to access anything else I get this error:

{
  "errorCode": "401",
  "appErrorCode": "",
  "errorMessage": "The user is not authorized to access this resource"
}

I am using a full admin account to access the API. 

I have looked at this documentation:

• https://apidocs.symantec.com/home/saep#_get_a_list_of_symantec_endpoint_protection_manager_groups
• https://<server>:<port>/sepm/restapidocs.html#/api...

I cannot find anywhere to give a user permission to access specific APIs. Is there a setting in the SEP Management Console that I'm missing?