Undelivered Mail Returned to Sender

From: <MAILER-DAEMON_at_FreeBSD.org (Mail Delivery System)>
Date: Tue, 02 Nov 2021 23:57:53 UTC
This is the mail system at host mx1.freebsd.org.

I'm sorry to have to inform you that your message could not
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For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
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                   The mail system

<freebsd-isp@mlmmj.nyi.freebsd.org> (expanded from <freebsd-isp@freebsd.org>):
    host mlmmj.nyi.freebsd.org[2610:1c1:1:606c::50:24] said: 554 5.7.1 Spam
    message rejected (in reply to end of DATA command)