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Microsoft が提供する Microsoft 365 のサービス正常性（EX405758）にて、一部のユーザーで Outlook デスクトップクライアントおよび Outlook on the web（OWA）を利用して電子メールメッセージを断続的に送信または開くことができないアドバイザリが発生していました。

本事象の影響を受けているユーザーでは、電子メールメッセージを送信しようとすると Non – Delivery Report（NDR）を受け取りますが、メッセージは意図した受信者に届きます。

利用したクライアントによっては、Non – Delivery Report（NDR）に以下のようなエラーメッセージが含まれている場合があります。

・”このメッセージは送信できませんでした。
後でメッセージを再送信するか、ネットワーク管理者に連絡してください。
・”あなたのメッセージは、意図した受信者の一部または全部に届きませんでした。”

現在は、影響のあるアップデートを元に戻す修正の展開が完了し、メッセージトラフィックが回復したことを確認しており、本事象が改善したことを確認しています。

この問題は、トラフィックの負荷分散を最適化し、電子メールの転送時間を改善することを目的とした最近のアップデートにコードの問題が含まれていたことにより発生し、影響した問題になります。

今後、同様の影響を防ぐためにアップデートの検証およびテスト手順を見直し、コードの問題がどのように見過ごされていたかについて検証に努めるとのことです。

この問題は、Outlook デスクトップクライアントおよび Outlook on the web（OWA）を利用して、電子メールメッセージを送信したり、開いたりしようとする一部のユーザーに影響を与えました。

Microsoft 365 のサービス正常性（EX405758）にて、一部のユーザーで Outlook デスクトップクライアントおよび Outlook on the web（OWA）を利用して電子メールメッセージを断続的に送信または開くことができないアドバイザリが発生していました。

利用したクライアントによっては、Non – Delivery Report（NDR）に以下のようなエラーメッセージが含まれている場合があります。

・”このメッセージは送信できませんでした。
後でメッセージを再送信するか、ネットワーク管理者に連絡してください。
・”あなたのメッセージは、意図した受信者の一部または全部に届きませんでした。”

August 4, 2022 3:24 AM – Service restored

・Title : Some users intermittently can’t send or open email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users were intermittently unable to send or open email via the Outlook desktop client and Outlook on the web.
・More info : Affected users received a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may have contained the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Final status : Our fix to revert the affecting update has completed and we’ve confirmed via telemetry that message traffic has been restored, confirming impact resolution.
・Scope of impact : This issue impacted some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Start time : Tuesday, July 12, 2022, 9:00 AM (12:00 AM UTC)
・End time : Sunday, July 31, 2022, 3:00 AM (7/30/2022, 6:00 PM UTC)
・Root cause : A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that lead to impact.
・Next steps : – We’re reviewing our update validation and testing procedures to better understand how the code issue was missed to better prevent similar future impact.
This is the final update for the event.

August 3, 2022 2:46 AM – Service restored

・Title : Some users intermittently can’t send or open email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are intermittently unable to send or open email via the Outlook desktop client and Outlook on the web.
・More info : This is an incremental update to provide the latest status on the issue.
・Current status : Our fix to revert the offending update is approximately 94 percent complete and we’re continuing to monitor as it approaches 100 percent, remediating impact for all users.
For complete details on this event, please reference the post from 6:30 PM UTC on August 1, 2022.
・Next update by : Thursday, August 4, 2022, 4:30 AM (8/3/2022, 7:30 PM UTC)

August 2, 2022 3:17 AM – Service restored

・Title : Some users intermittently can’t send or open email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are intermittently unable to send or open email via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : Our fix to revert the offending update hasn’t completed as forecasted, though it’s approximately 92 percent complete.
Our preliminary testing indicates a corresponding decrease in impacted users, thus most users are no longer impacted by this event.
We’re continuing to monitor the reversion process as it approaches 100 percent to ensure it completely remediates impact for all users.
・Scope of impact : This issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Start time : Tuesday, July 12, 2022, 9:00 AM (12:00 AM UTC)
・Root cause : A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that’s leading to impact.
・Next update by : Wednesday, August 3, 2022, 4:30 AM (8/2/2022, 7:30 PM UTC)

July 29, 2022 9:22 AM – Service restored

・Title : Some users intermittently can’t send or open email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are intermittently unable to send or open email via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages, but the message still arrives for the intended recipient(s).
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
Users can validate that they’re affected by this event by reviewing the NDR and finding “HResult (0x8004010F)” within the error message.
・Current status : We’ve confirmed in our testing environment that reverting the offending update resolves the underlining issue, and have initiated the process to the rest of the affected service environment.
We’re monitoring the progress of the revert throughout the upcoming weekend and anticipate that impact should be remediated by Monday, August 1, 2022.
・Scope of impact : This issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Start time : Tuesday, July 12, 2022, 9:00 AM (12:00 AM UTC)
・Estimated time to resolve : We anticipate reverting the update will be completed by Monday, August 1, 2022.
・Root cause : A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that’s leading to impact.
・Next update by: Tuesday, August 2, 2022, 4:30 AM (8/1/2022, 7:30 PM UTC)

July 28, 2022 9:10 AM – Service restored

・Title : Some users intermittently can’t send or open email messages via the Outlook desktop client and Outlook on the web
・User Impact : Users are intermittently unable to send or open email via the Outlook desktop client and Outlook on the web.
・More info : Affected senders receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.” or “Your message did not reach some or all of the intended recipients.”
Additionally, users may see delays or failures when opening messages or attachments in Outlook on the web with the associated errors :
“Your message cannot be displayed” and “Please check on your network or tried again later”
・Current status : We’re continuing to monitor as we’re reverting the offending update in our testing environment to ensure it repairs the problem without causing additional unforeseen impact.
Once the validation is successful, we’ll initiate the revert to the impacted environment to resolve the issue.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send or open email messages via the Outlook desktop client and Outlook on the web.
・Start time : Tuesday, July 12, 2022, 9:00 AM (12:00 AM UTC)
・Root cause : A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that’s leading to impact.
・Next update by: Friday, July 29, 2022, 10:30 AM (1:30 AM UTC)

July 28, 2022 2:28 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : We’ve confirmed that the recent update intended to optimize traffic load balancing introduced a code issue that’s causing this problem.
We’re reverting this update to remediate impact.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Root cause : A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that’s leading to impact.
・Next update by : Thursday, July 28, 2022, 10:30 AM (1:30 AM UTC)

July 27, 2022 8:29 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : We’re continuing our investigation of sample NDRs and the aforementioned update to identify the most effective path forward to remediation.
We’ll provide a remediation timeline once it becomes available.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Root cause : A recent update intended to optimize traffic load balancing may have introduced a regression that’s leading to impact.
・Next update by: Thursday, July 28, 2022, 4:00 AM (7/27/2022, 7:00 PM UTC)

July 27, 2022 6:18 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : Our investigation of sample NDRs provided by affected users indicates that a recent update intended to optimize traffic load balancing may have introduced a regression that’s leading to impact.
We’re reviewing the potentially offending update to confirm our findings and determine a path forward to remediation.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Next update by : Wednesday, July 27, 2022, 10:00 AM (1:00 AM UTC)

July 27, 2022 2:21 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : We’re continuing to examine message details from sample NDRs provided by affected users.
Additionally, we’re exploring whether a possible save conflict within the email-sending process may be contributing to the impact.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Next update by : Wednesday, July 27, 2022, 8:00 AM (7/26/2022, 11:00 PM UTC)

July 27, 2022 12:59 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : We’re analyzing details from sample NDRs received by some affected users so we can further understand the issue and determine our next steps toward remediation.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Next update by: Wednesday, July 27, 2022, 3:00 AM (7/26/2022, 6:00 PM UTC)

July 27, 2022 12:59 AM – Service restored

・Title : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web
・User Impact : Some users are unable to send email messages via the Outlook desktop client and Outlook on the web.
・More info : Affected users receive a Non-Delivery Report (NDR) when attempting to send email messages.
Depending on the client leveraged, NDRs may contain the following messages :
“This message could not be sent. Try sending the message again later, or contact your network administrator.”
“Your message did not reach some or all of the intended recipients.”
・Current status : We’re analyzing details from sample NDRs received by some affected users so we can further understand the issue and determine our next steps toward remediation.
・Scope of impact : Your organization is affected by this event, and this issue impacts some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
・Next update by: Wednesday, July 27, 2022, 3:00 AM (7/26/2022, 6:00 PM UTC)

July 26, 2022 11:03 PM – Service restored

・Title : Some users receive a Non-Delivery Report (NDR) when attempting to send email messages
・User Impact : Users receive a Non-Delivery Report (NDR) when attempting to send email messages.
・Current status : We’re analyzing system logs to determine our next troubleshooting steps.
・Scope of impact : Your organization is affected by this event, and this issue may impact any user sending email messages.
・Next update by : Wednesday, July 27, 2022, 1:00 AM (7/26/2022, 4:00 PM UTC)

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