In case you have your message broker installed in BTP there are view exceptions with respect to what is described in Outgoing Service (SAP to FSM).

Port 443 is predefined for HTTPS connections and considered a standard, that’s why it doesn’t even have to be explicitly entered when the web address starts with HTTPS

EXAMPLE

Using the address https://FSM_Message_Broker.cfapps.eu10.hana.ondemand.com taken from picture above and path /fsm/SendOutboundMessageService.