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Microsoft Investigates Multiple Issues in Classic Outlook

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Last updated
1 unique sources, 4 articles

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Microsoft has resolved a bug causing email delivery issues for some Classic Outlook users sending via Outlook.com, which previously prevented messages from reaching intended recipients and triggered 0x80070005-0x0004dc-0x000524 non-delivery reports. The issue primarily affected users with Outlook profiles linked to Exchange accounts or those with Exchange Online mail contacts sharing SMTP addresses. Microsoft deployed a server-side fix on April 3, 2026, though some users may still encounter temporary issues until OAuth tokens expire. Earlier investigations revealed that Microsoft was addressing multiple problems in classic Outlook, including mouse pointer disappearance that also impacted OneNote and other Microsoft 365 apps, synchronization and connection issues with Gmail and Yahoo accounts, and "Can't connect to the server" errors when creating groups with EWS enabled. Temporary workarounds were provided for these issues while Microsoft worked on permanent fixes.

Timeline

  1. 13.03.2026 18:53 3 articles · 25d ago

    Microsoft Investigates Sync and Connection Issues in Classic Outlook

    Microsoft confirms that a bug causing Gmail and Yahoo email synchronization problems in classic Outlook has been fixed in the Microsoft 365 service. The issue previously triggered 0x800CCC0F and 0x80070057 errors and stopped syncing as of February 26, 2026. Some users may still experience temporary sync issues until their OAuth tokens expire. Microsoft provided a workaround requiring deletion of registry entries for affected email addresses to force a sign-in prompt. The company continues investigating "Can't connect to the server" errors when creating groups with EWS enabled. The article also confirms that Microsoft has resolved a known issue preventing some Classic Outlook users from sending emails via Outlook.com. Affected users received non-delivery reports (NDRs) with 0x80070005-0x0004dc-0x000524 errors when sending or replying to emails, particularly when the Outlook.com account was linked to another Exchange account or had an Exchange Online mail contact with the same SMTP address. Microsoft deployed a server-side fix on April 3, 2026, and recommends using the New Outlook client or Outlook.com on the web as temporary workarounds until OAuth tokens expire.

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  2. 23.02.2026 21:40 2 articles · 1mo ago

    Microsoft Acknowledges Mouse Pointer Disappearance in Classic Outlook

    Microsoft has acknowledged a bug in classic Outlook that causes the mouse pointer to disappear, making the app unusable. The issue has been reported for nearly two months, and Microsoft is investigating while offering temporary workarounds. The same issue also affects some users of OneNote and other Microsoft 365 apps. Temporary workarounds include clicking an email, switching to PowerPoint, or restarting the computer.

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Information Snippets

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