MicrosoftRadar Independent status for Microsoft services

Users might be unable to sign in to OWA or send emails on Exchange Server

Microsoft lists this known issue for 4 Windows versions; its status is Resolved. It started with KB5126646, KB5126651, KB5126655 and 1 more updates. Microsoft resolved it in KB5131080, KB5131085, KB5131090 and 1 more updates.

Resolved1 version

Facts

Microsoft id
5047
Status
Resolved
Products
Windows 10, version 1607, Windows 10, version 1809, Windows Server 2016, Windows Server 2019, Windows Server 2022, Windows Server 2025
Versions
Windows 10, version 1607 and Windows Server 2016, Windows 10, version 1809 and Windows Server 2019, Windows Server 2022, Windows Server 2025
Originating KBs
KB5126646, KB5126651, KB5126655, KB5126868
Resolved by
KB5131080, KB5131085, KB5131090, KB5131291
First captured by us
Microsoft last modified
Source
Windows known issues · open the original at Microsoft

Status per Windows version

VersionStatusOriginating updateOpenedResolved
Windows Server 2025Resolved KB5131080OS Build 26100.33650, KB5126646, 2026-10-132026-11-10 03:07 UTC2026-11-10 18:00 UTC
Windows Server 2022Resolved KB5131090OS Build 20348.5761, KB5126655, 2026-10-132026-11-10 03:07 UTC2026-11-10 18:00 UTC
Windows 10, version 1809 and Windows Server 2019Resolved KB5131085OS Build 17763.9376, KB5126651, 2026-10-132026-11-10 03:07 UTC2026-11-10 18:00 UTC
Windows 10, version 1607 and Windows Server 2016Resolved KB5131291OS Build 14393.9612, KB5126868, 2026-10-132026-11-10 03:07 UTC2026-11-10 18:00 UTC

Microsoft says

After installing the October 2026 Windows security update (KB5126646), some on-premises Exchange servers might experience issues accessing or sending email.

Windows known issues,

Read Microsoft's full post

What Microsoft changed

One version so far. If Microsoft edits it, each change shows here with what was removed and added.

  1. First version we captured ·

    As first seen: Resolved
    Status
    Resolved

    Seen by us · Microsoft's timestamp · Microsoft's page

Mentioning the same Microsoft ids

Last updated