AT&T users face Microsoft 365 email delivery delay

If you are amongst the AT&T customers who are facing delays in Microsoft 365 email delivery, AT&T has its say about the issue. 

The news comes via BleepingComputer which reported that AT&T servers refused the connection and wouldn’t accept the email for delivery.

AT&T customers face delays in Microsoft 365 email delivery

The issue has plagued many customers who tried emailing an address at @att.com, @sbcglobal.net, or @bellsouth.com. Besides, customers reported that they saw the following reasons for the delay in email delivery:

Reason: [{LED=450 4.4.316 Connection refused [Message=Socket error code 10061] [LastAttemptedServerName=att.net] [LastAttemptedIP=144.160.159.21:25][SmtpSecurity=-2;-2] [MW2NAM10FT061.eop-nam10.prod.protection.outlook.com 2024-05-08T15:33:54.328Z 08DC6E49E2071EB6]};{MSG=Socket error code 10061};{FQDN=att.net};{IP=144.160.159.. OutboundProxyTargetIP:144.160.159.22. OutboundProxyTargetHostName: att.net

Reason: [{LED=450 4.4.316 Connection refused [Message=Socket error code 10061] [LastAttemptedServerName=bellsouth.net] [LastAttemptedIP=144.160.159.22:25] [SmtpSecurity=-2;-2] [CO1NAM11FT004.eop-nam11.prod.protection.outlook.com2024-05-08T15:54:34.984Z 08DC6EC21DF48CA1]};{MSG=Socket error code 10061};{FQDN=bellsouth.net};{IP=. OutboundProxyTargetIP: 144.160.159.22. OutboundProxyTargetHostName: bellsouth.net

One of the AT&T Community Forums users who self-claims as an IT system admin explains the above message. The user mentions that the message trace seen above hints that Microsoft 365 is unable to deliver an email to an ATT.net domain.

The reason for that is the connection is refused by the mail server of the recipient. It could be due to some configuration issue or firewall settings implemented by AT&T, the user adds.

Multiple AT&T customers reported email delays

Many AT&T customers are quite frustrated with the Microsoft 365 email delivery delay and have created multiple topics highlighting it. One such post is from the company’s forum user @silicondt who says:

Same problem. Can’t send from multiple 365 accounts or gmail…only to att.net domain… Hey ATT… I can’t even email your SALES guys… get this working…

It is worth noting that the issue is not only limited to Microsoft 365 customers, it also affects Gmail. One affected user posted:

I’m having the same problem: nothing from a Gmail account is getting into my email account (sbcglobal.net), and nothing is being bounced back to the sending Gmail accounts. It’s just vanishing. Yet everything was working a few hours ago. I haven’t changed ANY settings, have no blocked accounts, etc, etc. It was working this morning; it’s not working this evening. NOTHING I can do on my end will “fix” this issue. 

Come on, AT&T, get it together and fix the problem.

AT&T confirms the issue

AT&T has confirmed that an unusually high volume of spam that emerged from Microsoft’s server is eventually causing the email delivery delay. Talking more on it, the AT&T spokesperson further added:

This incoming spam is an industry-wide issue that affects multiple email services. We thank our customers for their patience as we work with Microsoft to help protect them from fraud

When the publication reached out to AT&T, Microsoft, and Google about the email delay issue, no further information was obtained. Worth noting that last month Microsoft announced that it would fight back against spam by adding a limit to the amount of bulk emails users send via Exchange Online.

Are you also facing a similar issue? If so, please let us know in the comments below.