{"id":16001,"date":"2026-04-18T03:01:25","date_gmt":"2026-04-17T18:01:25","guid":{"rendered":"https:\/\/m365jp.net\/?p=16001"},"modified":"2026-04-18T03:01:42","modified_gmt":"2026-04-17T18:01:42","slug":"servicerestored-ex1275040-exchange-online-users-may-be-unable-to-download-or-open-email-attachments-in-outlook-on-the-web","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-04-18-servicerestored-ex1275040-exchange-online-users-may-be-unable-to-download-or-open-email-attachments-in-outlook-on-the-web","title":{"rendered":"[serviceRestored] EX1275040 | Exchange Online | Users may be unable to download or open email attachments in Outlook on the web"},"content":{"rendered":"
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EX1275040 | Exchange Online | Users may be unable to download or open email attachments in Outlook on the web<\/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>\nadvisory<\/td>\n<\/tr>\n
User Impact<\/th>\nUsers may have been unable to download or open email attachments in Outlook on the web.<\/td>\n<\/tr>\n
Last Updated<\/th>\n04\/17\/2026 17:21:19<\/td>\n<\/tr>\n
Start Time<\/th>\n04\/09\/2026 04:00:00<\/td>\n<\/tr>\n
End Time<\/th>\n04\/17\/2026 17:00:00<\/td>\n<\/tr>\n
Latest Message<\/th>\nTitle: Users may be unable to download or open email attachments in Outlook on the web<\/p>\n

User impact: Users may have been unable to download or open email attachments in Outlook on the web.<\/p>\n

Final status: We’ve restarted the affected portion of infrastructure and confirmed through monitoring internal service health telemetry that the impact has been remediated.<\/p>\n

Scope of impact: Some users attempting to download or open email attachments in Outlook on the web may have been impacted.<\/p>\n

Start time: Thursday, April 9, 2026, at 4:00 AM UTC<\/p>\n

End time: Friday, April 17, 2026, at 5:00 PM UTC<\/p>\n

Root cause: An authentication issue on a portion of Outlook on the web infrastructure responsible for downloading and opening attachments was resulting in impact.<\/p>\n

Next steps:
– We’re reviewing the affected portion of Outlook on the web infrastructure to determine how the authentication issue was introduced, so that we can prevent similar instances of impact from occurring in the future.<\/p>\n

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

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\u7d42\u4e86\u6642\u523b:2026\u5e744\u670817\u65e5\u91d1\u66dc\u65e5 17:00 UTC<\/p>\n

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\u6b21\u306e\u30b9\u30c6\u30c3\u30d7:
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EX1275040 | Exchange Online | Users may be unable to download or open email attachments in Outlook on the web […]<\/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-16001","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/16001","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=16001"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/16001\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=16001"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=16001"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=16001"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}