Mandatory
This field specifies the reference to the entire message.
This field must not start or end with a slash ('/') and must not contain two consecutive slashes ('//') (Error code(s): T26).
The sender's reference must be unique for each message and is part of the message identification and transaction identification which is used in case of queries, cancellations, etc. This reference must be quoted in any related confirmation or statement, to the sending financial institution.