Error message in Scheduled Jobs History as "Error while publishing to queue: Connection failed."
SAP Integration Server, Winshutttle Central
Due to RabbitMQ service is stopped.
RabbitMQ is the queue application. RabbitMQ failures are almost some kind of operating system issue and we rarely see them. Restarting or start the RabbitMQ service from services.msc on the server resolves the issue.