Trouble getting mail delivered to Office365 (outlook.com), ProofPoint, and Barracuda protected domains
Date:
Tue, 22 Apr 2025 16:50:29 -0400
To:
eCS-ISP <ecs-isp@2rosenthals.com>
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
--
Lewis
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Lewis G Rosenthal, CNA, CLP, CLE, CWTS, EA
Rosenthal & Rosenthal, LLC www.2rosenthals.com
visit my IT blog www.2rosenthals.net/wordpress
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