Email delivery for **Microsoft Exchange Online** users is currently experiencing significant disruptions, characterized by delays and "Server busy" errors. The issue, tracked under **EX1467029**, primarily impacts the flow of email to and from external domains. **Microsoft** acknowledged the incident at 02:19 AM EDT, initiating an investigation into widespread reports. A service alert from **Microsoft** detailed the problem: "This issue impacts users who may be attempting to send and receive email messages from external domains in Exchange Online. Users may experience intermittent 'Server busy' errors, affecting multiple mailboxes." The company noted that while email clients should periodically retry sending affected messages, a Non-Delivery Report (NDR) might be issued after 24-72 hours, necessitating a new email from the sender. ### Anti-Spam Protections Aggravate Delays Adding to the complexity, **Microsoft** has identified that existing anti-spam protections might be inadvertently contributing to the problem for a subset of users. "Our initial investigation has identified instances where anti-spam protections may be contributing to impact for a subset of users," **Microsoft** stated, indicating ongoing analysis to pinpoint the underlying cause and determine the most effective mitigation strategies. ### Recent History of Exchange Online Issues This isn't an isolated incident for **Microsoft's** email service. In April, **Exchange Online** faced an outage preventing mailbox and calendar access across various **Outlook** platforms. Weeks later, intermittent access issues affected **Outlook** mobile and macOS users. More recently, in June, a similar service disruption impacted mail flow for customers across North America, Asia-Pacific (APAC), and Europe. Just this week, on Thursday, a massive outage caused authentication issues, connection problems, and service failures for **Microsoft 365** customers. ### Resolution for New Emails Reported As of September 04, 10:26 EDT, **Microsoft** has provided an update, indicating that the **EX1467029** issue has been resolved for new emails. "Telemetry shows that the service is performing as expected for new emails and this is in line with organizations confirming that the issue no longer occurring," **Microsoft** reported, with monitoring of email queues and final validations underway to confirm complete resolution.