{"id":15717,"date":"2026-04-02T03:01:11","date_gmt":"2026-04-01T18:01:11","guid":{"rendered":"https:\/\/m365jp.net\/?p=15717"},"modified":"2026-04-02T03:02:09","modified_gmt":"2026-04-01T18:02:09","slug":"servicerestored-ex1256020-exchange-online-some-users-may-be-intermittently-unable-to-access-their-exchange-online-mailboxes-in-some-connection-methods","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-04-02-servicerestored-ex1256020-exchange-online-some-users-may-be-intermittently-unable-to-access-their-exchange-online-mailboxes-in-some-connection-methods","title":{"rendered":"[serviceRestored] EX1256020 | Exchange Online | Some users may be intermittently unable to access their Exchange Online mailboxes in some connection methods"},"content":{"rendered":"
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EX1256020 | Exchange Online | Some users may be intermittently unable to access their Exchange Online mailboxes in some connection methods<\/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 intermittently unable to access their Exchange Online mailboxes in some connection methods.<\/td>\n<\/tr>\n
Last Updated<\/th>\n04\/01\/2026 17:06:38<\/td>\n<\/tr>\n
Start Time<\/th>\n03\/12\/2026 00:00:00<\/td>\n<\/tr>\n
End Time<\/th>\n03\/30\/2026 20:00:00<\/td>\n<\/tr>\n
Latest Message<\/th>\nTitle: Some users may be intermittently unable to access their Exchange Online mailboxes in some connection methods<\/p>\n

User impact: Users may have been intermittently unable to access their Exchange Online mailboxes in some connection methods.<\/p>\n

More info: This issue may have intermittently impacted some users who attempted to access the Exchange Online service through the Outlook mobile apps or the new Outlook for Mac desktop client.<\/p>\n

Final status: We’ve monitored the service for an extended period of time and confirmed that error counts have remained below pre-incident levels, confirming remediation.<\/p>\n

Scope of impact: Impact may have occurred for some users intermittently and users may have been unable to access their Exchange Online mailboxes with the Outlook mobile apps or the new Outlook for Mac desktop client. <\/p>\n

Start time: Thursday, March 12, 2026, at 12:00 AM UTC<\/p>\n

End time: Monday, March 30, 2026, at 8:00 PM UTC<\/p>\n

Root cause: A recent update intended to enable new Virtual Account functionality introduced a routing conflict that was preventing the Outlook mobile apps or the new Outlook for Mac desktop client from syncing to the Exchange service as expected, leading to impact.<\/p>\n

Next steps:
– We’re reviewing the impacting service update to determine why the routing conflict wasn’t identified through our pre-deployment testing processes, so that we can prevent similar instances of impact from occurring in the future.
– Additionally, we’re implementing additional optimizations on the service and client-sides to further reduce the error counts and make the service more robust.<\/p>\n

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

Machine Translation<\/th>\n\u30bf\u30a4\u30c8\u30eb:\u4e00\u90e8\u306e\u30e6\u30fc\u30b6\u30fc\u306f\u3001\u3042\u308b\u63a5\u7d9a\u65b9\u6cd5\u3067\u65ad\u7d9a\u7684\u306bExchange Online\u306e\u30e1\u30fc\u30eb\u30dc\u30c3\u30af\u30b9\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u306a\u3044\u5834\u5408\u304c\u3042\u308a\u307e\u3059<\/p>\n

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\u958b\u59cb\u6642\u9593:2026\u5e743\u670812\u65e5\u6728\u66dc\u65e5 0:00 UTC<\/p>\n

\u7d42\u4e86\u6642\u523b:2026\u5e743\u670830\u65e5(\u6708)\u5348\u5f8c8\u6642(UTC)<\/p>\n

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\u6b21\u306e\u30b9\u30c6\u30c3\u30d7:
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EX1256020 | Exchange Online | Some users may be intermittently unable to access their Exchange Online mailboxe […]<\/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-15717","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15717","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=15717"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15717\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=15717"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=15717"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=15717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}