Problem with smtp_client-1.1

[Roberto Saccon]

I try to use smtp_client (inside yaws, but also standalone) to send
e-mails, but I get an error when the SMTP-FiniteStateMachine starts to
send the message:

    mfrom_error "501 Bad address syntax\r\n"

the from-address in this case is:  rsaccon@REDACTED , and I don't
see what could be wrong with it. And all previous steps work fine,
including authentication.

the actual function executed when the error happens is:

     gen_fsm:sync_send_event(Fsm,{mfrom,Address}).


All  did was just compiling smtp_fsm.erl and run it form the erlang
shell (or inside my yaws app with same result). But I am erlang
novice, so maybe just my environmental setup is incomplete ? Or what
else could cause this strange error ?

regards
-- 
Roberto Saccon