{"id":15702,"date":"2026-04-01T06:01:03","date_gmt":"2026-03-31T21:01:03","guid":{"rendered":"https:\/\/m365jp.net\/?p=15702"},"modified":"2026-04-01T06:04:01","modified_gmt":"2026-03-31T21:04:01","slug":"servicerestored-ex1259460-exchange-online-some-users-may-be-unable-to-access-custom-add-ins-through-any-exchange-online-connection-method","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-04-01-servicerestored-ex1259460-exchange-online-some-users-may-be-unable-to-access-custom-add-ins-through-any-exchange-online-connection-method","title":{"rendered":"[serviceRestored] EX1259460 | Exchange Online | Some users may be unable to access custom add-ins through any Exchange Online connection method"},"content":{"rendered":"
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EX1259460 | Exchange Online | Some users may be unable to access custom add-ins through any Exchange Online connection method<\/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 access custom add-ins through any Exchange Online connection method.<\/td>\n<\/tr>\n
Last Updated<\/th>\n03\/31\/2026 20:45:28<\/td>\n<\/tr>\n
Start Time<\/th>\n03\/03\/2026 13:52:00<\/td>\n<\/tr>\n
End Time<\/th>\n03\/27\/2026 01:40:00<\/td>\n<\/tr>\n
Latest Message<\/th>\nTitle: Some users may be unable to access custom add-ins through any Exchange Online connection method<\/p>\n

User impact: Users may have been unable to access custom add-ins through any Exchange Online connection method.<\/p>\n

More info: For additional guidance on managing Exchange Web Services, please refer to the following:<\/p>\n

learn.microsoft.com\/en-us\/exchange\/client-developer\/exchange-web-services\/how-to-control-access-to-ews-in-exchange<\/a><\/p>\n

Final status: We\u2019ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following:
learn.microsoft.com\/en-us\/exchange\/client-developer\/exchange-web-services\/how-to-control-access-to-ews-in-exchange<\/a><\/p>\n

Scope of impact: Some users who are attempted to access custom add-ins through all Exchange Online connection methods may have been impacted. <\/p>\n

Start time: Thursday, March 12, 2026, at 10:04 PM UTC<\/p>\n

End time: Friday, March 27, 2026, at 1:40 AM UTC<\/p>\n

Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook.<\/p>\n

Next steps:
– We\u2019re reviewing how the impacting changes prevented users from accessing custom add-ins so we can avoid similar issues in the future, as EWS is slated to be deprecated by October 2026.<\/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\u3044\u304b\u306a\u308bExchange Online\u63a5\u7d9a\u65b9\u6cd5\u3067\u3082\u30ab\u30b9\u30bf\u30e0\u30a2\u30c9\u30a4\u30f3\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u306a\u3044\u5834\u5408\u304c\u3042\u308a\u307e\u3059<\/p>\n

\u30e6\u30fc\u30b6\u30fc\u3078\u306e\u5f71\u97ff:\u30e6\u30fc\u30b6\u30fc\u306fExchange Online\u306e\u63a5\u7d9a\u65b9\u6cd5\u3092\u901a\u3058\u3066\u30ab\u30b9\u30bf\u30e0\u30a2\u30c9\u30a4\u30f3\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u306a\u304b\u3063\u305f\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n

\u8a73\u7d30\u60c5\u5831:Exchange Web\u30b5\u30fc\u30d3\u30b9\u306e\u7ba1\u7406\u306b\u95a2\u3059\u308b\u8ffd\u52a0\u306e\u30ac\u30a4\u30c0\u30f3\u30b9\u306b\u3064\u3044\u3066\u306f\u3001\u4ee5\u4e0b\u306e\u3082\u306e\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\u3002<\/p>\n

learn.microsoft.com\/en-us\/exchange\/client-developer\/exchange-web-services\/how-to-control-access-to-ews-in-exchange<\/a><\/p>\n

\u6700\u7d42\u72b6\u6cc1:\u6700\u8fd1\u306eExchange Web Services(EWS)\u306e\u975e\u63a8\u5968\u5316\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3068Exchange Online\u8a8d\u8a3c\u306e\u5909\u66f4\u306b\u3088\u308a\u3001\u30e6\u30fc\u30b6\u30fc\u304cOutlook\u306e\u30ab\u30b9\u30bf\u30e0\u30a2\u30c9\u30a4\u30f3\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u306a\u304f\u306a\u3063\u305f\u3053\u3068\u304c\u5224\u660e\u3057\u307e\u3057\u305f\u3002\u3053\u306e\u554f\u984c\u3092\u662f\u6b63\u3059\u308b\u305f\u3081\u3001\u554f\u984c\u3068\u306a\u308b\u5909\u66f4\u3092\u30ed\u30fc\u30eb\u30d0\u30c3\u30af\u3057\u3001\u30b5\u30fc\u30d3\u30b9\u30e2\u30cb\u30bf\u30ea\u30f3\u30b0\u3092\u901a\u3058\u3066\u3053\u306e\u5bfe\u5fdc\u304c\u5f71\u97ff\u3092\u6b63\u5e38\u306b\u89e3\u6c7a\u3057\u305f\u3053\u3068\u3092\u78ba\u8a8d\u3057\u307e\u3057\u305f\u3002 EWS\u3092\u7121\u52b9\u306b\u3057\u305f\u7ba1\u7406\u8005\u306f\u3053\u306e\u554f\u984c\u304c\u7d9a\u304f\u53ef\u80fd\u6027\u304c\u3042\u308b\u305f\u3081\u3001\u73fe\u5728EWS\u3092\u518d\u6709\u52b9\u306b\u3059\u308b\u3053\u3068\u3092\u304a\u52e7\u3081\u3057\u307e\u3059\u3002Exchange Web Services\u306e\u7ba1\u7406\u306b\u95a2\u3059\u308b\u8ffd\u52a0\u306e\u30ac\u30a4\u30c0\u30f3\u30b9\u306b\u3064\u3044\u3066\u306f\u3001\u4ee5\u4e0b\u306e\u70b9\u3092\u53c2\u7167\u3057\u3066\u304f\u3060\u3055\u3044\u3002
learn.microsoft.com\/en-us\/exchange\/client-developer\/exchange-web-services\/how-to-control-access-to-ews-in-exchange<\/a><\/p>\n

\u5f71\u97ff\u7bc4\u56f2:\u3059\u3079\u3066\u306eExchange Online\u63a5\u7d9a\u65b9\u5f0f\u3092\u901a\u3058\u3066\u30ab\u30b9\u30bf\u30e0\u30a2\u30c9\u30a4\u30f3\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3059\u308b\u4e00\u90e8\u306e\u30e6\u30fc\u30b6\u30fc\u306f\u5f71\u97ff\u3092\u53d7\u3051\u3066\u3044\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n

\u958b\u59cb\u6642\u9593:2026\u5e743\u670812\u65e5\u6728\u66dc\u65e5 22:04 UTC<\/p>\n

\u7d42\u4e86\u6642\u523b:2026\u5e743\u670827\u65e5\u91d1\u66dc\u65e5 \u5348\u524d1\u664240\u5206 UTC<\/p>\n

\u6839\u672c\u539f\u56e0:\u6700\u8fd1\u306eEWS\u5ec3\u6b62\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3068Exchange Online\u8a8d\u8a3c\u306e\u5909\u66f4\u306b\u3088\u308a\u3001\u30e6\u30fc\u30b6\u30fc\u304cOutlook\u306e\u30ab\u30b9\u30bf\u30e0\u30a2\u30c9\u30a4\u30f3\u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u306a\u304f\u306a\u308a\u307e\u3057\u305f\u3002<\/p>\n

\u6b21\u306e\u30b9\u30c6\u30c3\u30d7:
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\u3053\u308c\u304c\u30a4\u30d9\u30f3\u30c8\u306e\u6700\u7d42\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3067\u3059\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

EX1259460 | Exchange Online | Some users may be unable to access custom add-ins through any Exchange Online co […]<\/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-15702","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15702","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=15702"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/15702\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=15702"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=15702"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=15702"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}