OAuth token expired or revoked: re-authentication required

The OAuth 2.0 access token has reached its expiration time and the refresh token has also expired, requiring complete re-authentication with the external service provider. (high likelihood)

The external service provider has revoked the OAuth application credentials or changed security policies, invalidating existing tokens for your ServiceNow instance. (high likelihood)

The OAuth Entity record in ServiceNow contains incorrect or outdated client credentials (client ID, client secret) that prevent successful token refresh operations. (medium likelihood)

Network connectivity issues or firewall restrictions are preventing ServiceNow from reaching the OAuth provider's token endpoint for refresh operations. (medium likelihood)

The OAuth provider's token endpoint URL has changed or the service is temporarily unavailable, causing refresh attempts to fail and tokens to be marked as invalid. (low likelihood)

Step 1: Navigate to System Web Services > Outbound > OAuth Entity and locate the OAuth Entity record associated with the failing integration to examine its current token status.

Step 2: Check the System Log at System Diagnostics > Log > System Log for detailed OAuth-related error messages that occurred around the same time as the authentication failure.

Step 3: Verify that the OAuth Entity record contains correct and current client credentials by comparing the Client ID and Client Secret with values provided by the external service provider.

Step 4: Test network connectivity to the OAuth provider's token endpoint by using System Diagnostics > Network > Test Network Connection or checking ECC Queue entries for outbound communication errors.

Step 5: Clear existing tokens by opening the OAuth Entity record and clicking the 'Get OAuth Token' button to initiate a fresh authentication flow with the external provider.

Step 6: Complete the OAuth authorization process in the popup window, ensuring you have appropriate permissions in the external system to grant access to your ServiceNow instance.

Step 7: Test the integration by manually executing the affected REST Message or Integration Hub action to verify that OAuth authentication is now working correctly.

Step 8: Monitor the System Log for the next 24 hours to ensure token refresh operations are successful and no additional authentication errors occur.