Lewis,

Yes I am seeing weird messages from user screens saying dan@cihcsp.com is not a valid email!
I am using barracuda as a mail scanner. Both the cloud and a hardware device in my own server room.  I am baffled because I do not see any blacklisting or other information.  I am using DNS running the latest bind from our friend from down under a arcanoae  the mail server in question is running on linux.

YOS
Dan Napier


-----Original Message-----
From: eCS ISP Mailing List [mailto:ecs-isp@2rosenthals.com]
Sent: Tuesday, April 22, 2025 1:50 PM
To: eCS ISP Mailing List <ecs-isp@2rosenthals.com>
Subject: [eCS-ISP] Trouble getting mail delivered to Office365 (outlook.com), ProofPoint, and Barracuda protected domains

Hi, all...

For the past few days, I've been dealing with an issue of mail from
2rosenthals.com apparenly getting blackholed by certain providers. We do not
receive any kind of DSN. From all accounts, the email is going out for
delivery and that's that. However, on the other end, recipients aren't
seeing the messages, nor are they getting any kind of spam notification or
other warning that a message could not be delivered.

Affected domains seem to be hosted with a handful of providers, Office365
among them, which uses outlook.com. Naturally, I've checked both the
outlook.com and live.com internal lists, and both show that neither of our
IPs is listed.

Other MXs which seem to be behaving similarly are:

gpphosted.com (ProofPoint)
barracudanetworks.com

Multiple multiple-RBL checks come up clean for both IPs and our domain. SPF,
DKIM, and DMARC configurations all look fine (read: pass specific checks by
various third parties, including mxtoolbox.com).

Mail flows without incident to gmail.com and yahoo.com.

Is anyone else seeing anything like this?

TIA