iOS Outlook/Teams cannot sign in my account since Microsoft Defender Endpoint is not reachable

Question

iOS Outlook/Teams cannot sign in my account since Microsoft Defender Endpoint is not reachable

Xander Judge 5 Microsoft Employee

I am trying to login to my Microsoft account for Outlook and Teams. I have the VPN on and running with connect on demand enabled. I am logged in to Microsoft Defender and "Everything looks good" with device protection active and network protection secured. I am running iOS version 26.4 (current latest as of 4/5/2026). I am restarted, updated both teams and outlook. I have restarted my iOS device twice. I've restarted the VPN twice and tried signing out of Outlook and Teams and re-signing in. None of these actions seem to resolve the Microsoft Defender Endpoint being reachable. Thank you for any advice or guidance.

[Moved from Microsoft 365 and Office | Microsoft 365 Defender | For home | iOS]

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Answer 1

Hi @Xander Judge

The fact that Microsoft Defender displays "Everything looks good" can not necessarily mean that the Entra registration token is valid.

Microsoft explicitly states that the device must be registered with Microsoft Entra ID through Microsoft Authenticator. Therefore, even if Defender reports a healthy status, it is still possible that there is an issue with the device registration or authentication token that could prevent successful sign-in. You can review this article : https://learn.microsoft.com/en-us/defender-endpoint/mtd

Without reviewing the device's Entra Device Registration status, Intune Compliance status, and Microsoft Defender Device Risk status, it is not possible to determine the root cause with certainty. These three checks are required to verify whether the device is properly registered, compliant with organizational policies, and reporting a healthy security posture to Microsoft services.

If this device is connected to a corporate tenant (using Intune/Conditional Access), as the tenant administrator can check:

Entra Device Registration status,
Intune Compliance status,
Defender Device Risk status,

If you are not experiencing any issues with the checks mentioned above, I can suggest two steps that may help resolve the problem.

First, remove all VPN configurations from your device and then set up the VPN again.
Second, remove your account from Microsoft Authenticator, re-add it, and complete the MFA challenge during the enrollment process.

Once both steps have been completed, please try signing in to Outlook and Teams again. I believe this approach is likely to resolve the issue.