Microsoft is working on an Exchange Online outage that is delaying email sent to and received from external domains, according to BleepingComputer, which cited a Microsoft service alert for incident EX1467029. BleepingComputer reports that Microsoft first acknowledged the issue at 02:19 AM EDT after investigating reports of intermittent “Server busy” errors. The alert said the problem affects users attempting to send and receive messages involving external domains in Exchange Online, and that the errors can affect multiple mailboxes. According to BleepingComputer, Microsoft has not disclosed which regions are affected, how many users are impacted, or when it expects full remediation. One early lead in Microsoft’s investigation is anti-spam handling. BleepingComputer quotes Microsoft as saying its initial review found instances where anti-spam protections may be contributing to the impact for a subset of users, potentially adding further delays for affected accounts. The company is still reviewing service telemetry and analyzing behavior to determine the underlying cause and the most effective mitigation path, BleepingComputer reports. That keeps the incident in an operationally active state rather than a resolved postmortem. BleepingComputer also cited recent Microsoft 365 and Exchange Online disruptions as background, such as an April Exchange Online outage affecting mailbox and calendar access, a June mail-flow issue affecting customers in North America, Asia-Pacific and Europe, and a Microsoft 365 outage earlier this week involving authentication, connection, service-delay and failure issues. Those prior incidents are background only; the provided material does not establish that they share a cause with EX1467029. Who benefits: There is no clear commercial beneficiary from the provided reporting. Who's exposed: Users attempting to send and receive messages involving external domains in Exchange Online are exposed to the reported delays and intermittent errors. The scope remains unclear because Microsoft has not disclosed affected regions or user counts in the provided material.