sender verify fail for noreply@letsencrypt.org: response to "RCPT TO:noreply@letsencrypt.org" from aspmx.l.google.com [2a00:1450:400c:c05::1b] was: 550-5.1.1 The email account that you
tried to reach does not exist.
Please don't use a non-existant (non-deliverable) sender address for any email exchange (verification), including (but obviously not limited to) community verification; there are systems which verify the deliverability of the sender and reject email with fake sender, making it impossible to get the mail with the magic link.
If you don't care about replies please send them to /dev/null
locally, but let's make it possible to validate the source. (No, I do not suggest not to use SPF, DK, BATV or any other techniques.)
Thanks for your helping attitude in advance!