A developer receives a 401 Unathorized HTTP status message from a REST API request.

A 401 Unauthorized HTTP status message indicates that the request was not authenticated properly. This error commonly occurs when the access token is missing, invalid, or expired.

Access Token Issues: The most common cause of a 401 error in REST API requests is related to the access token. The request must include a valid access token in the authorization header.

Example Authorization Header: Authorization: Bearer YOUR_ACCESS_TOKEN

Salesforce API Access Tokens