Message from Outlook.com - Undeliverable

Question

Outlook emails undelivered to AT&T/Yahoo email addresses:

Receive the following message from Microsoft Outlook

Undeliverable: Delivery has failed to these recipients or groups:

I receive this message when an email is sent to either an att.net or sbcglobal.net address. I have checked with the recipient and the email does not show up in the their Spam/Junk folder and I am not on any blocked email address listing.

Would appreciate any help to resolve this issue.

Regards,

Jim T

Answer 1

Based on past history (Google "AT&T's email servers are blocking connections from Microsoft 365") it would appear that the AT&T/Yahoo SPAM filters may periodically block emails from entire domains and specific email addresses. When this happens you get a bounced notification and the email will not show up anywhere in your recipient's email client.

The only suggestion I can offer is to test sending to a few of the AT&T/Yahoo email addresses from a different email provider (e.g. GMail). But that will only help you confirm the problem, not solve it. Sorry.