Microsoft Exchange / IPhone email syncing problem

Question

Microsoft Exchange / IPhone email syncing problem

Ray King 5

I have a microsoft exchange business account on my windows laptop. I store emails that i want to keep in exchange folders. I use outlook for my email and sync my email to my iPhone. about two days ago, I can no longer see on my iphone the emails that reside on the microsioft exchange server. They eamils are not syncing between my windows laptop and my iphone. I have already deleted the email app on my iphone and then reloaded it (twice). tThis problem started after an iphone system update 2 days ago. Has anyone experienced this problem? How do resolve this problem?

Ken S 0 Reputation points

2026-10-24T13:05:43.26+00:00

Same problem. I have an iphone 16. Everything works fine (we use Microsoft 365 or whatever). Got the new iphone duo on friday and my work calender wont sync to my apple calendar at all. My emails will sync but only through Thursday and I can't send any emails from my phone.

Does IT need to approve my device?

The outlook app works fine for the calendar, email, etc. though.
Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-26T21:54:15.94+00:00

Hi Ken,

Thank you for sharing your experience. Have you had a chance to try the troubleshooting steps I provided in my answer below?

Kind regards,

1 answer

Your answer

Ken S 0 Reputation points

2026-10-24T13:05:43.26+00:00

Same problem. I have an iphone 16. Everything works fine (we use Microsoft 365 or whatever). Got the new iphone duo on friday and my work calender wont sync to my apple calendar at all. My emails will sync but only through Thursday and I can't send any emails from my phone.

Does IT need to approve my device?

The outlook app works fine for the calendar, email, etc. though.
Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-26T21:54:15.94+00:00

Hi Ken,

Thank you for sharing your experience. Have you had a chance to try the troubleshooting steps I provided in my answer below?

Kind regards,

Answer 1

Clover-L 110 Microsoft External Staff Moderator

Hi Ray King,
Thank you for reaching out to the Microsoft Community.

As a forum moderator, I am not able to access your account or delve into the backend systems to diagnose and fix this for you. My role here is limited to providing general guidance and solutions for users to implement themselves.

Please try the following:

Sign in to Outlook on the web and confirm whether the missing emails and folders are available there.
On your iPhone, go to Settings > Apps > Mail > Mail Accounts > Exchange.
Confirm that Mail is enabled.
Select Mail Days to Sync, then choose No Limit.
If the issue continues, select Delete Account, restart the iPhone, and add the account again from Settings > Apps > Mail > Mail Accounts > Add Account > Microsoft Exchange.

Removing the account from the iPhone will not delete emails stored in your Exchange mailbox.

As a temporary workaround, you can access your email through Outlook on the web or install the Microsoft Outlook app on your iPhone.

If the issue persists, please provide the following additional details:

Do the missing emails appear in Outlook on the web?
Are you using Apple Mail or Microsoft Outlook on the iPhone?
Does the issue affect all folders or only specific folders or older messages?
Is anyone else in your organization experiencing the same issue?
Were any other changes made around the time the issue started, such as changes to the iPhone, Exchange account, Outlook settings, security policies, or authentication settings?

Kind regards

Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-26T21:21:55.33+00:00

Hi Ray King,
I’m following up to check whether you managed to complete the action plan shared.

Please let me know if the issue persists or if you have any questions or concerns.
Ray King 5 Reputation points

2026-10-26T21:59:54.7433333+00:00

I did what was suggested and did not solve the problem.
Ray King 5 Reputation points

2026-10-26T22:04:42.93+00:00

I've deleted the account then reistalled the account. This did not solve the problem. The emails do appear in Outlook on the web. They also exist in my Outlook email program. But they do not appear in the Excange sub-folders on my Iphone.
Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-27T18:14:19.4566667+00:00
Hello Ray King,

Thank you for the update. Since the emails appear in Outlook on the web and Outlook for Windows, the issue appears limited to mobile synchronization.

Please try the following:

Go to Settings > Apps > Mail > Mail Accounts > Exchange and turn Mail off.

Sign in to your Microsoft 365 account, open Manage account > Devices, select the affected iPhone, and remove it.

Restart the iPhone, then return to the Exchange settings and turn Mail back on.

Allow some time for the folders to synchronize.

If the issue continues, ask your Microsoft 365 administrator to check the mailbox’s Exchange ActiveSync partnerships and any recent mobile-access, security, or authentication policy changes.

I also recommend installing the Microsoft Outlook app for iPhone and adding the same account. This is the preferred option for accessing a Microsoft 365 business mailbox on an iPhone.

Please let me know whether the subfolders appear in the Outlook app.

For reference please check this article : Email items missing on a mobile device after synchronization with Exchange ActiveSync | Microsoft S…

Kind regards,
Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-28T20:56:07.3833333+00:00

Hi Ray King,

Just following up to see how you're getting on with the second action plan.

Is the issue still popping up on your end? Let me know if you run into any questions or need a hand with anything.
Cap_Romchik 0 Reputation points

2026-10-29T06:39:35.8+00:00

We have the same problem on some phones in our company. We have reseted phones, re-install accounts but nothing resolve the problem. The phone is allowed on Exchange, have the actuality Intune police but when we add the email account on the phone we see "downloading messages" and empty any folders. It`s happing endlessly. We see allowed requests with status 200 on our reverse proxy when I try to refresh the phone app but it doesn't help. The phone doesn't show the emails. It's like the account problem because we added another account on that phone and it works fine. I have no ideas who to fix that.
Clover-L 110 Reputation points Microsoft External Staff Moderator

2026-10-29T21:23:15.25+00:00
Hi Cap_Romchik,

Because another Exchange account works on the same iPhone, while this account remains at“Downloading messages” with empty folders, the iOS update and reverse proxy are less likely to be the main cause. This points more strongly to the affected mailbox’s Exchange ActiveSync partnership, mailbox policy, or synchronization state. An HTTP 200 from the reverse proxy only confirms that the request reached a server. It does not confirm that the ActiveSync response contained a successful synchronization result.

I wish we could inspect the mailbox and ActiveSync logs directly, but the following checks must be performed by the Exchange administrator.

1.Confirm the server copy of the email

Sign in to Outlook on the web with the affected account and verify that the folders and messages are visible there. Also confirm that the folders shown in desktop Outlook are under the Exchange mailbox, not under:

Archive Folders

On My Computer

A local .pst file

A separate shared mailbox

Local Outlook folders do not synchronize to the iPhone. If the same messages appear in Outlook on the web, continue with the server-side checks.
2. Check the iPhone synchronization range

On the iPhone, go to:

Settings > Apps > Mail > Mail Accounts > Exchange account > Mail Days to Sync

Temporarily select 1 Month rather than No Limit, then reopen Mail. Apple notes that large Exchange mailboxes can take considerably longer to synchronize, and limiting the initial mail range can help.

Also make sure Mail is enabled under the account. If this account is deployed through Microsoft Intune, check the Exchange ActiveSync configuration profile’s Past days of mail to sync value as well.
3. Remove the existing device partnership

Deleting and reinstalling the iPhone Mail app does not necessarily remove the device partnership stored in Exchange. Have your exchange administrator remove the affected iPhone partnership so Exchange creates a fresh one. Microsoft specifically recommends Remove-MobileDevice for partnerships that no longer synchronize successfully.

For example:

Get-MobileDevice -Mailbox ******@contoso.com | Format-Table Identity,DeviceType,DeviceModel,DeviceOS,DeviceAccessState

Get-MobileDeviceStatistics -Mailbox ******@contoso.com | Format-List Identity,DeviceID,DeviceType,DeviceOS,LastSuccessSync,LastSyncAttemptTime,DeviceAccessState,DeviceAccessStateReason

Identify the current iPhone carefully, then remove only that partnership:

Remove-MobileDevice -Identity "<device identity>" -Confirm:$false

After removal:

Delete the Exchange account from Settings > Apps > Mail > Mail Accounts.

Restart the iPhone.

Add it again using Add Account > Microsoft Exchange > Sign In.

Complete the modern-authentication prompt.

Initially synchronize only one month of mail.

For reference: Remove-MobileDevice (ExchangePowerShell) | Microsoft Learn

4.Have your exchange adminstrator compare with a working account:

Get-CASMailbox ******@contoso.com | Format-List ActiveSyncEnabled, ActiveSyncMailboxPolicy,ActiveSyncAllowedDeviceIDs,ActiveSyncBlockedDeviceIDs

Confirm that:

ActiveSyncEnabled is True.

The affected and working users have the expected ActiveSync policy.

The current iPhone is not in ActiveSyncBlockedDeviceIDs.

The device is not quarantined or subject to a restrictive device-access rule.

Exchange administrators can allow or block a specific device for a specific user, even when ActiveSync is generally enabled.
Cap_Romchik 0 Reputation points

2026-11-02T13:18:40.7433333+00:00

Hi Clover-L

Thanks for your feedback.

I've tried that you advised but it's no result. I've removed MobileDevice from our Exchange server and added the phone again.

Now on Exchange I see that:

FirstSyncTime : 02.11.2026 12:21:37

LastPolicyUpdateTime : 02.11.2026 12:21:39

LastSyncAttemptTime : 02.11.2026 12:37:35

LastSuccessSync : 02.11.2026 12:37:35

DeviceType : OutlookService

DeviceUserAgent : OutlookServiceMrsAgent

LastPingHeartbeat :

DeviceModel : OutlookService

DeviceOS : OutlookModernAuth

Status : DeviceOk

DeviceAccessState : Allowed

DeviceAccessStateReason : Individual

DevicePolicyApplied : Default

DevicePolicyApplicationStatus : AppliedInFull

ClientVersion : 16.1

NumberOfFoldersSynced : 1

ClientType : EAS

IsValid : True

On Reverse proxy I see requests from his account with status 200.

count of requests

FolderSync&User 25

ItemOperations&User 22

Options&User 24

Provision&User 2

Sync&User 44

My cowoker can see all his email from owa but the phone does't recieve any emails.
Cap_Romchik 0 Reputation points

2026-11-03T08:38:17.76+00:00

Hi Clover-L,

I remembered one more thing. We tried another test. We configured email account with native mail app (iPhone) without Intune for my coworker who had problem and it worked perfectly while his was on vocation for 2 weeks. It was for test. But policy of our company requires to work by protected channel with MDM (Intune). I am concerned by the lack of a ping request to the Microsoft Cloud / Outlook service.

Is it possible that the issue lies on the Microsoft Cloud side, and how can this be verified?