Microsoft Investigates Exchange Online Mailbox Access Issues After Incident Returns

Microsoft has confirmed that it will support Exchange Server until 2035, but Exchange Online is currently facing reliability problems. The company is now investigating an ongoing issue that affects mailbox access across several platforms.

Issue resurfaces after being marked resolved

The problem impacts users trying to access mailboxes through Outlook mobile apps and the new Outlook for Mac. Reports indicate that the issue has been occurring intermittently for several weeks.

Microsoft initially tracked the disruption under incident ID EX1256020 and marked it as resolved on April 1. However, the issue returned shortly after and is now being tracked again as EX1268771, suggesting that the underlying cause was not fully addressed.

Microsoft testing mitigation steps

The company believes the issue may be linked to a newly introduced virtual account. To mitigate the problem, Microsoft has started restarting the Notification Broker service in affected parts of its infrastructure.

These efforts aim to stabilize mailbox access, but Microsoft has not confirmed whether the mitigation fully resolves the issue.

Intermittent failures continue

Users affected by the incident experience intermittent mailbox access failures, making it difficult to reliably check emails. The issue does not impact all users consistently, which complicates troubleshooting and root cause analysis.

Microsoft has classified the situation as a service incident, indicating a serious disruption, and continues to investigate. The company has not shared details about the scale of the outage or which regions are most affected.

Microsoft is working on identifying the root cause and implementing a long-term solution to prevent similar issues in the future. Until then, users may continue to encounter occasional access problems.

In other news, Microsoft recently provided a workaround for an issue that prevents sending emails in Classic Outlook.

Via BleepingComputer