Security News > 2024 > May > AT&T delays Microsoft 365 email delivery due to spam wave
AT&T's email servers are blocking connections from Microsoft 365 due to a "High volume" spam wave originating from Microsoft's service.
Starting on Monday, AT&T customers began reporting they could no longer receive email from Microsoft 365 email addresses.
"Same problem. Can't send from multiple 365 accounts or gmail... only to att.net domain... Hey ATT... I cant even email your SALES guys... get this working...," reported someone trying to send an email to an AT&T address.
"An unusually high volume of spam originating from the Microsoft email platform is causing temporary delays in receiving emails from that platform," an AT&T spokesperson told BleepingComputer.
"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."
Microsoft recently announced it will fight spam originating from its platform by imposing a daily Exchange Online bulk email limit of 2,000 external recipients starting January 2025.
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