{"id":15536,"date":"2026-03-24T04:01:14","date_gmt":"2026-03-23T19:01:14","guid":{"rendered":"https:\/\/m365jp.net\/?p=15536"},"modified":"2026-03-24T04:01:24","modified_gmt":"2026-03-23T19:01:24","slug":"servicedegradation-ex1259159-exchange-online-some-users-outbound-email-messages-may-display-unexpected-sender-name-in-exchange-online","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-03-24-servicedegradation-ex1259159-exchange-online-some-users-outbound-email-messages-may-display-unexpected-sender-name-in-exchange-online","title":{"rendered":"[serviceDegradation] EX1259159 | Exchange Online | Some users\u2019 outbound email messages may display unexpected sender name in Exchange Online"},"content":{"rendered":"
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EX1259159 | Exchange Online | Some users\u2019 outbound email messages may display unexpected sender name in Exchange Online<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n\n\n\n\n\n\n\n\n\n\n
Status<\/th>\nserviceDegradation<\/td>\n<\/tr>\n
Classification<\/th>\nadvisory<\/td>\n<\/tr>\n
User Impact<\/th>\nUsers\u2019 outbound email messages may display unexpected sender name in Exchange Online.<\/td>\n<\/tr>\n
Last Updated<\/th>\n03\/23\/2026 18:49:48<\/td>\n<\/tr>\n
Start Time<\/th>\n03\/23\/2026 07:42:58<\/td>\n<\/tr>\n
End Time<\/th>\n<\/td>\n<\/tr>\n
Latest Message<\/th>\nTitle: Some users\u2019 outbound email messages display unexpected sender name in Exchange Online<\/p>\n

User impact: Users\u2019 outbound email messages display unexpected sender name in Exchange Online.<\/p>\n

More info: When affected users send email to external recipients, the sender name shown may be the mailbox DisplayName instead of the configured SimpleDisplayName.<\/p>\n

Current status: We\u2019re confirming whether the update identified is causing impact and whether this can be safely reverted as a mitigation step. In parallel, we\u2019re evaluating alternative mitigation options. We\u2019ll provide an update once a mitigation path is confirmed.<\/p>\n

Scope of impact: Some users sending email to external recipients in Exchange Online may be impacted. This information may be updated as our investigation continues.<\/p>\n

Root cause: A recent service update introduced new outbound mail behavior that caused Exchange Online to stop honoring the configured SimpleDisplayName in some outbound email scenarios, resulting in impact.<\/p>\n

Next update by: Monday, March 23, 2026, at 8:30 PM UTC<\/td>\n<\/tr>\n

Machine Translation<\/th>\n\u30bf\u30a4\u30c8\u30eb:\u4e00\u90e8\u306e\u30e6\u30fc\u30b6\u30fc\u306e\u9001\u4fe1\u30e1\u30fc\u30eb\u306bExchange Online\u3067\u4e88\u671f\u3057\u306a\u3044\u9001\u4fe1\u8005\u540d\u304c\u8868\u793a\u3055\u308c\u308b<\/p>\n

\u30e6\u30fc\u30b6\u30fc\u3078\u306e\u5f71\u97ff:\u30e6\u30fc\u30b6\u30fc\u306e\u9001\u4fe1\u30e1\u30fc\u30eb\u306bExchange Online\u3067\u4e88\u671f\u3057\u306a\u3044\u9001\u4fe1\u8005\u540d\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n

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\u6839\u672c\u539f\u56e0:\u6700\u8fd1\u306e\u30b5\u30fc\u30d3\u30b9\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3067\u3001Exchange Online\u304c\u4e00\u90e8\u306e\u9001\u4fe1\u30e1\u30fc\u30eb\u30b7\u30ca\u30ea\u30aa\u3067SimpleDisplayName\u306e\u8a2d\u5b9a\u3092\u5c0a\u91cd\u3057\u306a\u304f\u306a\u308a\u3001\u5f71\u97ff\u304c\u751f\u3058\u307e\u3057\u305f\u3002<\/p>\n

\u6b21\u56de\u66f4\u65b0:2026\u5e743\u670823\u65e5(\u6708)\u5348\u5f8c8\u664230\u5206(UTC)<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

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