I have no way to login the Busniess Teams account

Even though this thread was posted from a zh-tw location, you’ve used English in your description, so I will continue supporting this case in English for clarity and consistency.

Dear @JERRY HUANG,

Thank you for posting your question in the Microsoft Q&A forum. I understand you’re unable to sign in to your Microsoft Teams (business) account because your company phone with the Microsoft Authenticator app was lost, and the sign-in now asks for an approval code.

This is expected behavior. Your account is protected by multi-factor authentication (MFA), so even with the correct password, sign-in cannot complete without an approved verification method. Reinstalling Teams or retrying the password alone will not bypass MFA.

To restore access, you can try those options below:

If you are users or have other admins in your company, please contact them and ask to revoke MFA sessions. This will allow you to sign in and set up Microsoft Authenticator again on a new phone. For step-by-step details, refer to the official Microsoft documentation: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID | Microsoft Learn  

If you are the only admin and no other admin is available, access can only be recovered through Microsoft’s account recovery process, where tenant ownership must be verified. Please contact the Data Protection Team directly via phone support - Customer service phone numbers - Microsoft Support.

Microsoft Data Protection team has only required permission to reset your account on the backend. They are the only responsible and privileged support team for account questions.

During the phone call, you will be required to provide the information associated with your subscription - such as your company name, billing details, phone number, and alternate email address - to verify ownership of the company’s tenant. This verification will assist the Data Protection Team in granting you access to the administrator account.

Please carefully follow this instruction to ask for Microsoft Data Protection team support:   

Depending on your country or region. For some countries, when calling the support number, although there are about 30 seconds opening as something "you can visit the link...." But you can ignore this opening and wait until the option, then "1" as a business email user, "1" again for technical help.    For some countries, it will be an automated conversation like:    

• First, when you call the hotline, it asks what kind of problem you are worried about.    Answered: authenticator.   
• A: What kind of product are you using?   
• B: Office 365 for business.   
• A confirmation: education or company account?   
• B: For companies   
• A: Are you an administrator?   
• B: Yes.   
• A: Do you have the other admin in your organization?   
• B: No.   
• A: You need one.... Service request?   
• B: Yes   

If your organization's Office 365 Business/Education subscription is from a partner or reseller, and the global administrator is unable to open a service request on your end, contact the reseller's support provider to help open a service request on behalf of you instead.   

Please understand that forum moderators have no control over user accounts, especially when it comes to logging in to your account, resetting your password, changing your access, etc.   

Alternatively, you can try set up a new trial tenant and submit your support request: 

1. Start a free trial: Go to Compare Office 365 Enterprise Pricing and Plans | Microsoft 365.  and click Try for free to create a new tenant.
2. Complete setup: Follow the guided steps to create a new Microsoft account and tenant.
3. Access Admin Center: Sign in at https://admin.microsoft.com.
4. Open Support: In the left menu, select Support > Help & support.
5. Submit a ticket: Clearly state you are locked out of a different tenant where you are the admin. Include: Admin account email, Tenant domain name, Error messages, Issue details, Confirmation you are the administrator
6. Track your request: Submit and note the ticket number.

Important notes:  

• The trial tenant won’t give access to your original tenant’s data or settings; it’s only for contacting Microsoft support.
• Support may require identity and admin rights verification for the locked tenant.
• Resolution could take longer because you’re contacting from a different tenant.
• Please do not forget cancel the trial subscription after resolving the issue to avoid charges (Admin Center > Billing > Your products)

Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.

I truly appreciate your patience and understanding. If you have any further questions or need further clarification, please feel free to reach out. I'm looking forward to hearing from you. 

Thank you for your cooperation.

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