On 18.04.2023 at 19:18 A. Schulze via mailop wrote:
Am 12.04.23 um 17:02 schrieb Paul Menzel via mailop:
>> Since March 29th, 2023 we have not received any (MTA-STS) TLS reports from
>> microsoft.com.
> it seems it's not only TLS reporting: more then once over the last days we
> received
As far as I can see, envelope-from domains without a SOA record see their email
rejected with 554 over some volume threshold.
This seems to be a fairly recent update. This requirement only recently
appeared here: https://senders.yahooinc.com/smtp-error-codes/ (you can check
the internet archive
