MS Outlook no longer able to connect to IMAP server

SDN 0 Reputation points
2026-11-12T21:03:10.14+00:00

Just received a push update from Windows; now my local MS Outlook can no longer connect to the IMAP servers (which have not been changed). Something gone wrong with the updates?

Outlook | Windows | Classic Outlook for Windows | For home
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  1. Estrella721 47,875 Reputation points Independent Advisor
    2026-11-12T21:35:00.27+00:00

    Microsoft is currently experiencing a service disruption affecting Outlook and other Microsoft 365 services. The issue is on Microsoft's end, so there is nothing you need to do on your device or account for now. I recommend waiting until Microsoft resolves the issue and normal service is restored.

    You can follow the latest updates through the official channels below:

    Microsoft Service Status: https://status.cloud.microsoft/

    Microsoft 365 Status on X: https://x.com/MSFT365Status/status/2120938282204688468

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  2. AI answer

    2026-11-12T21:03:23.71+00:00

    A Windows update can be related, but the documented Outlook-specific causes are narrower than “the update broke IMAP” in general.

    For classic Outlook on Windows, the two supported causes/workarounds in this scenario are:

    1. App password issue If the IMAP provider uses app passwords, create a new one in the provider’s webmail security settings, then update it in Outlook:
      • In Outlook, go to File.
      • Under Account Information, select the affected IMAP account.
      • Select Account Settings > Server Settings.
      • Paste the new app password into the Password box.
      • Select Next, then Done.
    2. TLS 1.3 on Windows 10 Microsoft documented that TLS 1.3 may cause IMAP/POP connection errors on Windows 10, while Windows 11 TLS 1.3 should work fine with Outlook. If the PC is on Windows 10 and the failure started after an update, this is a known workaround:
      • Open Regedit.
      • Go to: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols
      • If TLS 1.3 exists under Protocols, export the key first so it can be restored if needed.
      • Delete the TLS 1.3 key and its subkeys.
      • Restart Outlook. If sync still does not resume, restart Windows.
      Warning: editing the registry is a high-risk change. Export the key first so the setting can be reverted.

    If Outlook is also showing setup-type errors such as Autodiscover failed or Invalid IMAP server info, the next supported step is to get the exact IMAP server name and port from the email provider and sign in again using advanced settings.

    If the account is an Exchange Online mailbox being configured in Outlook with IMAP/SMTP, another documented cause is authentication mode: Outlook does not support Modern authentication for POP/IMAP Exchange profiles. In that case, IMAP/SMTP connectivity depends on Basic authentication being enabled for those protocols.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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