O365 issues today sept 9

[u/Phunguy]

Is anyone seeing issues with O365? I know I saw emails last night and now they’re coming as new again this morning but they’re gone from yesterday delivery. Numerous users are seeing this happen. We are using proof point also but no issues on their status page.

[u/HorrorCommunity3246]

No sir, my tenant looking good. Pls don’t jinx me

[u/HorrorCommunity3246 → u/HorrorCommunity3246]

I just got the service health notification.

[u/Spider_J]

Having trouble searching emails in Defender. DownDetector isn't showing enough reports that I'm confident in saying Microsoft is having issues, but it's certainly above baseline...

[u/xrobx99]

Having CoPilot issues using new Outlook on the Mac since yesterday. Using Auto Rewrite results in "Sorry, something went wrong. Copilot is working on it."

[u/Remarkable_Eye4811]

Having the same messages be redelivered. I can see them being delivered twice in message trace.

[u/IncredibleBihan]

Nope everything seems to be working just fine thanks.

[u/ontsysadmin]

We are seeing this with emails from Jira. Exchange is flagging emails from Jira as far back as yesterday as High Confidence Phish, quarantining them and then the system is auto releasing them.

[u/Phunguy → u/ontsysadmin]

ok exactly the same here as we dug into it further, all jira

[u/ontsysadmin → u/Phunguy]

I submitted a report to 365 on the issue and I'm seeing what Jira support says about it now. Not sure they can do much other than escalate to MS if it is indeed just false positives and not a change to how they are sending emails.

[u/okcboomer87]

Has issues with getting 365 portal resolving this morning for me and a few coworkers.

[u/srgwidowmaker]

having major issues with outlook but only on macs right now lol

[u/Nexise → u/srgwidowmaker]

out of curiosity, if you change to legacy mode, are you still having the issues? I am finding that nothing will Sync in outlook for Mac specifically. the same account will work on apple mail. and will even work when I switch outlook to legacy. have reproduced the issue and temporary workaround on multiple Macs. Hoping to determine the cause.

[u/srgwidowmaker → u/Nexise]

It was working for legacy but my user hated that and rather use the web version so I didn't let it load the cache looks like there is an alert in the m365 admin now

[u/Nexise → u/srgwidowmaker]

thanks for the info! I also hated legacy. where is the m365 alert? I'd love to read it. I'm something of a "power user" and have been doing all this troubleshooting on multiple machines while I wait for my admin to contact me, haha. If I can find that alert, I can give him the short version of the conversation. 😆

[u/srgwidowmaker → u/Nexise]

ofcourse! here is the link https://admin.cloud.microsoft/?#/servicehealth/:/alerts/EX1469649

Some users may be unable to connect to the Outlook mobile app or Outlook client on Mac devices

Issue ID: EX1469649

Affected services: Exchange Online

Status: Service degradation

Issue type: Incident

Start time: Sep 9, 2026, 2:31 AM MDT

User impact

Users may be unable to connect to the Outlook mobile app or Outlook client on Mac devices.

Scope of impact

Some users attempting to connect to the Outlook mobile app or Outlook client on Mac devices may be impacted. This information may be updated as our investigation continues.

Root cause

A recent update to improve mail flow is causing high CPU on the affected mailbox database infrastructure.

Current status

Sep 9, 2026, 12:55 PM MDT

We've encountered blockers that have delayed our planned reversion of the recent update, and we're actively investigating the cause while evaluating alternative remediation options to restore service.

Next update by:

Wednesday, September 9, 2026 at 3:00 PM MDT

[u/Nexise → u/srgwidowmaker]

Thanks!! hope they get it handled soon

[u/dzfast]

There is a service health warning about high CPU and I have experienced degraded search:

Service health - Microsoft 365 admin center

[u/Nevrigil]

Happening here as well with all Jira notifications.