{"id":247070,"date":"2026-11-11T07:09:53","date_gmt":"2026-11-11T13:09:53","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2026\/11\/microsoft-fixes-exchange-sign-ins-broken-by-windows-server-updates"},"modified":"2026-11-11T07:09:53","modified_gmt":"2026-11-11T13:09:53","slug":"microsoft-fixes-exchange-sign-ins-broken-by-windows-server-updates","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2026\/11\/microsoft-fixes-exchange-sign-ins-broken-by-windows-server-updates","title":{"rendered":"Microsoft fixes Exchange sign-ins broken by Windows Server updates"},"content":{"rendered":"\n<p>Microsoft has fixed Outlook sign-in and mail delivery issues on Exchange Server systems after installing the October 2026 Windows Server security updates.<\/p>\n<p>Microsoft <a href=\"https:\/\/www.bleepingcomputer.com\/news\/microsoft\/microsoft-october-windows-server-updates-cause-exchange-issues\/\" target=\"_blank\" rel=\"nofollow noopener\">acknowledged this known issue<\/a> in mid-October, confirming that users had trouble accessing email or signing in to Outlook after installing the latest updates on systems running Windows Server 2019 and later.<\/p>\n<p>As explained at the time, the sign-in and mail flow issues are caused by a new default limit on the amount of memory Endpoint Mapper uses when handling Endpoint Lookup calls, introduced by the October 2026 updates.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Microsoft has fixed Outlook sign-in and mail delivery issues on Exchange Server systems after installing the October 2026 Windows Server security updates. Microsoft acknowledged this known issue in mid-October, confirming that users had trouble accessing email or signing in to Outlook after installing the latest updates on systems running Windows Server 2019 and later. As [\u2026]<\/p>\n","protected":false},"author":427,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1492],"tags":[],"class_list":["post-247070","post","type-post","status-publish","format-standard","hentry","category-security"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/247070","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/427"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=247070"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/247070\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=247070"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=247070"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=247070"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}