Problem

-- getting such warning at runtime in the Message Log "message stopped". No output created by map on output 'out2'."
-- no output message is created

Resolution

* such error usually occur on a mpping services flow, when optionnal outputs are not generated at runtime : typically when an Event type error generates an output and no error occurs at runtime

* open the related Processing Step -> "Action when no output created by flow:" -> change the setting accordingly (typically : from "error" to 'ignore")