API requests return authentication errors after token expiration

Symptom

REST API requests return authentication errors such as HTTP 401 Unauthorized. Long-running automation or API client operations terminate unexpectedly after a period of normal operation.

Cause

Smart Update Manager (SUM) REST APIs use bearer-token-based authentication, and access tokens are valid for a limited time. Requests that use expired access tokens are rejected by the authentication service.

Action

  1. Configure API clients to detect authentication errors.
  2. If a refresh token is available, use the refresh token workflow to obtain a new access token.
  3. If a refresh token is unavailable or the token refresh does not complete successfully, authenticate again and obtain a new access token.
  4. Use the new access token for all subsequent API requests.
  5. Do not reuse expired access tokens.