can't use teams on my mobile device

Dear Rebekah Redd,

Thank you for providing a detailed update regarding your situation.

Based on the information shared, it appears that you have already performed extensive troubleshooting. In addition, your previous organization has attempted to remove your account from their environment; however, the issue continues to persist after an extended period of time. This indicates that the issue may be more complex and potentially related to backend configurations or residual policies associated with your account or device.

Given that the issue has been ongoing for over a week and may be time sensitive, I recommend contacting the IT team within your current organization. They can assist in raising a support request ticket with Microsoft. This will enable the Microsoft support team to conduct a more in-depth investigation and provide guidance tailored to your specific environment.

The Global Admin can create a support ticket by sign in to the Microsoft 365 Admin Center > Support > Help & Support.  

For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin.     

Note: If you’re an end-user, please coordinate with your Office 365 Global Administrator to handle these steps.

Please note that this is a user-to-user support forum. My role is limited to providing general guidance, and I do not have access to internal systems or the ability to review account-level configurations. For this reason, engaging your organization’s IT team to escalate the issue is the most appropriate next step.

I hope this information is helpful. If you need any further assistance, please feel free to reach out.
Thank you very much for your understanding and cooperation.

The behavior is consistent with a sign-in and account configuration issue tied to the old organization’s Microsoft 365/Entra configuration on the device.

Based on the available information, the only supported and reliable paths are:

1. Work with the new organization’s IT admin
   • The new company’s Microsoft 365/Entra admin must verify that:
     • The correct work account is enabled, licensed for Teams, and not blocked.
     • Conditional Access or MDM/Intune policies allow sign-in from your device/platform.
   • If the device is enrolled in the new company’s MDM/Intune, they should:
     • Confirm the device record is healthy and compliant.
     • Remove any old app configuration profiles or app protection policies that might still reference the previous tenant.
2. Ensure the correct account is used in Teams
   • On the mobile device, completely sign out of all Microsoft apps (Teams, Outlook, Office, etc.).
   • In the Teams mobile app:
     • Remove any personal or old work accounts from within Teams (if possible) so only the new work account remains.
     • Sign in only with the new company’s work account.
   • If the app still tries to use the old tenant, this indicates the device or app is still associated with the old organization’s identity or MDM profile, which only IT admins can fully clear.
3. If sign-in is blocked by MFA or repeated attempts
   • If multiple failed sign-in attempts or MFA prompts have occurred, Microsoft Entra multifactor authentication may temporarily block sign-in as a security measure. In that case:
     • Wait before trying again, or
     • Use a different MFA method if one is configured (for example, SMS or another verification method).
   • If there is suspicion of misconfigured MFA or malicious activity, the organization’s IT admin must review Microsoft Entra sign-in logs and MFA settings and correct them.
4. When device reset is considered
   • For Teams-certified Android devices, if all other sign-in options fail, the documented last resort is a factory reset of the device, then deleting the device object in Microsoft Entra ID/Intune/Teams admin center so fresh objects are created on next sign-in.
   • A similar principle applies to other mobile devices: if the device remains logically tied to an old tenant despite removal attempts, the only guaranteed way to clear all residual management and app data may be a full device reset, followed by:
     • Re-enrollment only into the new organization’s MDM/Intune (if required).
     • Fresh installation of Teams and sign-in with the new work account.
   • This is destructive (all local data is wiped), so it should be done only after confirming with the new company’s IT that all required corporate data is backed up or cloud-based and that they expect this to resolve the tenant conflict.
5. If still blocked and there is only one admin in a tenant
   • If the account is an admin account and is locked due to MFA or sign-in issues and there is no other admin who can reset it, the tenant’s global admin must work with Microsoft’s Data Protection team via a support ticket raised from Microsoft 365 support channels. This is the only way to regain access when no other admin can fix the configuration.

In summary, the fix requires:

• Ensuring only the new organization’s account and policies are applied to the device.
• Having the new organization’s IT admin verify and, if needed, reset sign-in/MFA/MDM/Intune configuration for the account and device.
• As a last resort, performing a full device reset and re-enrolling only with the new organization.

References:

• Why am I having trouble signing in to Microsoft Teams?
• How to log in to Microsoft Teams
• What you can do in the Microsoft 365 apps on mobile devices with a Microsoft 365 subscription
• Common problems with two-step verification for a work or school account
• Certified Android devices get signed out of Teams