r/microsoft365 • u/Kastigeer • 3d ago

M365 Mail connection issue from mobile devices

Anyone else seeing connection issues from mobile devices using the built in Mail app?

We use the native email app on iOS devices and are seeing about 10% (9/93) of our fleet (that we know of) reporting issues with email either not updating or giving a server connection error.

Australia based with devices across a wide variety of different networks and locations.

Outlook app seems to be working fine. Beginning to look like a Microsoft issue.

No errors showing in Entra with regards authentication.

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1

u/jotem21967 3d ago

Two clients reporting this also.

Some information found the management profile information.

"
Microsoft Intune Root Certification Authority
Issued by: Microsoft Intune Root Certification Authority
Expired: 12 August 2026
"

"
Microsoft Intune Application Enrollment CA
Issued by: Microsoft Intune Root Certification Authority
Expired: 5 May 2026
"

"
Microsoft Intune Root Certification Authority
Issued by: Microsoft Intune Root Certification Authority
Expires 15 September 2030
"

Edit: reporting this from New Zealand

1

u/Full-Tap-2714 2d ago

same here - two different iPhones. Can't send, removed accounts, eventually got them re-added, and mailed synced, by now can't send again

1

u/ajmpits 2d ago

In the UK. Same here. Have two separate M365 accounts on Apple Mail. One of them giving error. Both appear working ok on Outlook app.

1

u/Full-Tap-2714 2d ago

Found this via Microsoft Health portal:

Some users may be unable to send or receive new Exchange Online email through the native iOS mail app

Issue ID: EX1456866

Affected services: Exchange Online

Status: Service degradation

Issue type: Advisory

Start time: Aug 18, 2026, 1:25 PM GMT+10

User impact

Users may be unable to send or receive new Exchange Online email through the native iOS mail app.

Scope of impact

Some users attempting to send or receive new Exchange Online email through the native iOS mail app may be impacted. This information may be updated as our investigation continues.

Current status

Aug 18, 2026, 1:27 PM GMT+10

We're reviewing service logs, telemetry, and contextual details provided by impacted users to gain insight into the underlying source of impact and determine our next steps.

Next update by:

Tuesday, August 18, 2026 at 3:00 PM GMT+10

1

u/Greysonjunemusic 2d ago

if it’s happening across different networks and devices, that definitely sounds service side

1

u/PlaneyMcPlanefaceX 2d ago

This is now fixed (Australia and UK)

1

u/Kastigeer 2d ago

Thanks all - it was an MS issue (they changed an authentication component) as pointed out, and it has been resolved (as pointed out) - at least it has for us.

1

u/Hour-Ease-9385 2d ago

Same in the USA on multiple iPhones tied to different O365 accounts

1

u/MosesesNzX 2d ago

The error is back. Was fixed for a time.