MAIL app can't access mail server, the iphone is DEP. How to

If your iPhone is unable to access the mail server using the MAIL application, there are several potential causes and solutions to consider:

1. TLS Version: Ensure that your Exchange server is configured to use TLS 1.2 or later. Older versions of Exchange Server that use TLS 1.0 or 1.1 may not be compatible with the MAIL app on your iPhone. If your Exchange server is running an outdated version, consider upgrading it.
2. Valid TLS Certificate: Check if the TLS certificate used by your Exchange server is valid and correctly installed. An expired or improperly configured certificate can prevent access.
3. Network Connectivity: Verify that your iPhone has a stable internet connection. If you're on a corporate network, ensure that there are no firewall or proxy settings blocking access to the mail server.
4. Account Settings: Double-check the account settings in the MAIL app to ensure they are correct, including the server address, username, and password.
5. DEP Configuration: Since your iPhone is DEP (Device Enrollment Program), ensure that the device management settings do not restrict access to the mail server.

If the issue persists after checking these factors, you may need to consult with your IT administrator for further assistance.

Hi Gao, Bryan,

Thank you for posting your question in the Microsoft Q&A forum. 

From your description, I understand that you have a DEP-enrolled iPhone and you are using the native Mail application to access your emails. However, after signing in, you encounter the error message: “Can’t access mail server.” Is that correct?

Based on my research and common scenarios, here are a few possible causes and suggestions:

• Ensure that the device has a stable internet connection, as the Mail app requires reliable connectivity to sync emails from the server. Please verify Network Connectivity, restart the network or reset network settings if necessary.
• Sometime, the issue may be related to the Mail app itself. Reinstall the Mail app and attempt to sign in again.
• If organizational policy permits, download and sign in using Microsoft Outlook for iOS. If Outlook works but the Mail app does not, this typically indicates that Conditional Access or App Protection policies are restricting the native Mail app.

As this is a DEP device, it is subject to Mobile Device Management (MDM) and Intune policies. In this case, I highly recommend you contact your IT administrator to verify whether any policy is blocking Mail app access or the device is missing required configurations.

I hope the suggestions above helpful. If you have any further update, please feel free to share.

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Interestingly we are seeing this issue across our intune iPhones, until now it has been with newer enrolled devices and it seams to occur weeks after the enrolment. I have also not found a solution to this, re-pushing the exchange profile doesn't work, forcing the users sessions out doesn't work, retiring and reenrolling manually doesn't work.

The only way to come back from this is a full wipe!