Microsoft to Fix Outlook Syncing Issues Caused by Broken Exchange ActiveSync Connections

Key Takeaways:

• Microsoft has acknowledged a new issue that is currently preventing some Outlook users from connecting to email servers via Exchange ActiveSync.
• The bug impacts all Outlook users who installed Office 365 version 2401, which was released last month.
• Microsoft has provided a temporary workaround to help affected users address the problem on their computers.

Microsoft has acknowledged a new issue affecting select Outlook users, which prevents the desktop apps from connecting to email servers through Exchange ActiveSync. The company confirmed that this issue impacts Office 365 customers who have installed the update (version 2401) released on January 9.

Exchange ActiveSync (EAS) is a protocol that allows mobile devices to synchronize data with Microsoft Exchange Server. It enables users to access information such as contacts, emails, calendars, and tasks even when they are offline. The protocol helps to ensure that any changes made on one device are reflected across all devices that are connected to Exchange Server. EAS also supports various security features to protect sensitive data in case a device is lost or stolen.

According to a Reddit thread, several users have been complaining about the broken ActiveSync connections since the beginning of February 2024. Users reported that they’ve been experiencing a problem recently where their emails aren’t syncing properly with the email server. In some cases, the email messages automatically disappear from users’ inboxes after a few days.

Fortunately, Microsoft is investigating the problem and a fix is expected to be available in the coming weeks. “After updating to Version 2401 Build 17231.20182 Outlook stops connecting when using the Exchange ActiveSync (EAS) protocol,” Microsoft explained. “The Outlook Team is investigating this issue. We will update this topic when the fix status is available.”

How to fix broken Exchange ActiveSync connections affecting Microsoft Outlook

In the meantime, Microsoft recommends Office 365 users in the Current Channel to revert the Office M365 Click-to-Run installations to version 2312 (Build 17126.20132). Alternatively, users can choose to switch to the Semi-Annual Channel to address the ActiveSync connection problems affecting Outlook desktop apps.

In related news, Microsoft is also investigating a bug that triggers Outlook security alerts when a user attempts to open .ICS calendar files. The problem was caused by the Patch Tuesday Office security updates released in December 2023.