pak Syafril jika gagal kirim dengan keterangan seperti ini kenapa pak?

terimaksih sebekum nya...

This is the mail system at host

I'm sorry to have to inform you that your message could not be delivered to
one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own
text from the attached returned message.

                   The mail system

<>: host[]

    said: 550 <>, Recipient unknown (in reply

    RCPT TO command)

Milis ini untuk Diskusi antar pengguna MDaemon Mail Server.

Dokumentasi :
Henti Langgan: Kirim mail ke
Versi terakhir MD 16.5.2, SP 5.0.1, OC 4.0.1, SG 4.0.1

Kirim email ke