{"id":15558,"date":"2026-03-25T01:01:30","date_gmt":"2026-03-24T16:01:30","guid":{"rendered":"https:\/\/m365jp.net\/?p=15558"},"modified":"2026-03-25T01:06:25","modified_gmt":"2026-03-24T16:06:25","slug":"servicerestored-ex1260428-exchange-online-some-users-may-have-been-unable-to-access-their-exchange-online-mailboxes-using-the-outlook-desktop-client-2","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-03-25-servicerestored-ex1260428-exchange-online-some-users-may-have-been-unable-to-access-their-exchange-online-mailboxes-using-the-outlook-desktop-client-2","title":{"rendered":"[serviceRestored] EX1260428 | Exchange Online | Some users may have been unable to access their Exchange Online mailboxes using the Outlook desktop client"},"content":{"rendered":"
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EX1260428 | Exchange Online | Some users may have been unable to access their Exchange Online mailboxes using the Outlook desktop client<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n\n\n\n\n\n\n\n\n\n\n
Status<\/th>\nserviceRestored<\/td>\n<\/tr>\n
Classification<\/th>\nincident<\/td>\n<\/tr>\n
User Impact<\/th>\nUsers may have been unable to access their Exchange Online mailboxes using the Outlook desktop client.<\/td>\n<\/tr>\n
Last Updated<\/th>\n03\/24\/2026 15:44:00<\/td>\n<\/tr>\n
Start Time<\/th>\n03\/24\/2026 05:40:00<\/td>\n<\/tr>\n
End Time<\/th>\n03\/24\/2026 13:00:00<\/td>\n<\/tr>\n
Latest Message<\/th>\nTitle: Some users may have been unable to access their Exchange Online mailboxes using the Outlook desktop client<\/p>\n

User impact: Users may have been unable to access their Exchange Online mailboxes using the Outlook desktop client.<\/p>\n

More info: Impacted users may have received a 401 error message.<\/p>\n

Final status: We\u2019ve confirmed that reverting the change successfully remediated the impact and restored the service.<\/p>\n

Scope of impact: Some users attempting to access their Exchange Online mailboxes via the Outlook desktop client may have been impacted.<\/p>\n

Start time: Tuesday, March 24, 2026, at 5:40 AM UTC<\/p>\n

End time: Tuesday, March 24, 2026, at 1:00 PM UTC<\/p>\n

Root cause: A recent service change introduced an unexpected behaviour that prevented part of the service from operating as designed, resulting in impact.<\/p>\n

Next steps:
– We’ll continue to closely monitor the service to ensure it remains healthy.
– We’re reviewing our deployment procedures to better identify similar issues during our development and testing cycles.<\/p>\n

This is the final update for the event.<\/td>\n<\/tr>\n

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EX1260428 | Exchange Online | Some users may have been unable to access their Exchange Online mailboxes using […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-15558","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15558","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/comments?post=15558"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15558\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=15558"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=15558"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=15558"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}