When sending out emails with a
MAIL FROM address > 81 characters I receive bounce messages from some MTAs:
501 Syntax error - Badly formatted address. (in reply to MAIL FROM command)
As soon as I change the
MAIL FROM address to <= 81 characters, the MTA accepts my message.
I didn't find any limits in the RFC docs.
Is this expected behaviour or is the recipients' MTA misconfigurated?