A Mule implementation uses an HTTP Request within an Until Successful scope to connect to...

Until Successful is intended for failures that can reasonably succeed when retried, such as temporary connectivity issues or transient downstream unavailability. Mule executes the processors in the scope repeatedly until processing succeeds or the configured retry count is exhausted. If an error continues to propagate from the scope, Mule performs another attempt and ultimately raises MULE:RETRY_EXHAUSTED after all retries fail.

An HTTP:UNAUTHORIZED response represents a permanent application/security condition for the current request. Repeating the identical request does not normally repair invalid credentials or insufficient authorization and simply increases latency and downstream traffic.

The HTTP Request should therefore be placed inside a Try scope. An On Error Continue handler specifically catches the permanent error and handles it inside that Try scope. Because the error is consumed rather than propagated, the Until Successful scope does not interpret the attempt as a retryable failure.

Using On Error Propagate would have the opposite effect: the error would escape the Try scope and cause Until Successful to retry. Continuing until MULE:RETRY_EXHAUSTED unnecessarily delays the response.

Reference topics: Until Successful Scope; Try Scope; On Error Continue; permanent versus transient errors; MULE:RETRY_EXHAUSTED.

Official documentation: https://docs.mulesoft.com/mule-runtime/latest/until-successful-scope

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