Subject: [sidr] Undelivered Mail Returned to Sender

From: [email-masked] (Mail Delivery System)
Date: Fri, 20 Dec 2019 06:04:20 -0800 (PST)

This is the mail system at host ietfa.amsl.com.

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
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                   The mail system

<[email-masked]>: Host or domain name not found. Name service error
    for name=signlikeme.com type=AAAA: Host found but no data record of
    requested type

Subject: Confirm: [email-masked]:Xfu7rALTQLtY:1V4bNjeaeeRmTdmy49vB6x1pmGpo_MNEtV6bKA
From: [email-masked]
To: [email-masked]
Date: Thu, 19 Dec 2019 10:04:28 -0800 (PST)

Confirmation of list posting -- confirmation ID: Xfu7rALTQLtY

The ietf.org mailing-list server has received a list posting from 
[email-masked] to [email-masked] with the subject 
'=?UTF-8?B?UmVhbGlzdGljIE1vb24gTGFtcCAtIEZsb2F0cyBpbiBNaWQgQWly?='

As the sender address isn't subscribed to the list, and has not been
confirmed earlier, we have to request a confirmation of the address.
To confirm the address, send a message to [email-masked],
with the same subject line as this message.

(Simply sending a 'reply' to this message should work from most email
interfaces, since that usually leaves the subject line in the right
form.  The reply's additional "Re:" is ok.)

If you do not wish your posting to the list to go through, simply
disregard this message.  Questions to [email-masked].