Unable to login to Microsoft 365 Central Administration

Question

I can't sign in "Microsoft 365 Central Administration" with second step verification.

Can I cancel second step verification or change to phone SMS verification.

My 365 main account email is [Moderator note: personal info removed] , Microsoft 365 Central Administration login email is**[Moderator note: personal info removed]** 

I added [Moderator note: personal info removed]  to Microsoft Authenticator, but I didn't receive a message during the second step verification.

[Moderator note: personal info removed] 

Alternative login method. I tried logging in via SMS, but it failed!

[Moderator note: personal info removed] 

BR,

Justin

Answer 1

Hi @Justin Chen,

To protect your privacy and ensure the security of your personal information, I’ve removed any sensitive details from your public post and sent you a private message. You can check your private messages by clicking the banner at the top of the page, as shown in the image below.

I’m really sorry that you’re running into this issue. Unfortunately, this is a user‑to‑user support forum, and forum moderators do not have access to user accounts or the ability to make changes related to account sign‑in, MFA settings, password resets, or authentication methods. That said, I’m more than happy to guide you through the next steps so you can move forward and work toward regaining access as smoothly as possible.

If you’re an administrator and you’re unable to authenticate, the next steps depend on whether there is anyone else in your organization with admin rights. If another admin exists, they should be able to reset your MFA settings for you so you can sign in again.

If you’re the only administrator in your tenant, the only path forward is to contact Microsoft Support directly by phone. In situations like this, the Microsoft Data Protection team has dedicated tools and verification processes to confirm your identity and help restore access to administrator accounts safely. You can find the correct phone number for your region here: Customer service phone numbers - Microsoft Support

Here are some tips and an example of a prompt to help you navigate the IVR more effectively: 

(When you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help.)   

In some regions, the initial interaction may be automated, so here’s a general idea of how the conversation might go to help you prepare:     

What kind of problem are you experiencing?        

Answer: Authenticator        

What products do you use?        

Answer: Office 365 for business        

Is this for an education or company account?        

Answer: For companies        

Are you an administrator?        

Answer: Yes        

Are there any other administrators in your organization?        

Answer: No. I am the only admin in my tenant         

Do you need a... Service request?         

Answer: Yes. I need to create a ticket. Please send me direct to the Data Protection Teams.     

During the phone call, you will need to provide the information associated with your subscription, such as your company name, billing details, phone number, and an alternate email address, etc. This information allows the Data Protection team to verify your identity and securely assist you in regaining access to your administrator account.   

I hope this information helps you take the right steps to regain access to your account. If you have any updates or additional details, please feel free to leave a comment under this post. I’ll be happy to assist further within my scope. 

Thank you for your understanding!

---

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.  

Answer 2

Error code 399287 indicates that the phone number used for SMS verification has been blocked by Azure due to a “bad reputation” flag, so SMS cannot be used as a second factor until Microsoft clears that flag. This also prevents switching MFA to SMS successfully.

For a work/school (Microsoft 365) tenant where sign‑in is blocked and there is no working alternative MFA method, the only supported way to regain access or reset MFA is through an administrator or Microsoft support:

1. If there is another global administrator in the tenant, that admin must:
   • Sign in to the Microsoft Entra admin center.
   • Go to Users → All users → [your account] → Authentication methods.
   • Use Require re‑register multifactor authentication to reset MFA so that new methods (Authenticator, SMS, etc.) can be configured.
2. If the locked account is the only administrator for the tenant, the case must be escalated to the Microsoft Data Protection team via Microsoft Support. Frontline support can open a ticket and the Data Protection team can:
   • Verify identity and ownership of the tenant.
   • Reset MFA settings and, where applicable, clear the bad‑reputation flag on the phone number so that SMS can be used again.

Community moderators and forum tools cannot remove the 399287 flag or disable MFA; this can only be done by Microsoft support or another tenant admin with the appropriate rights.

Until the Data Protection team or another admin resets MFA and clears the phone number reputation, second‑step verification cannot be cancelled or switched to SMS for that admin account.

---

References:

• Azure has blocked myphone number for SMS verification due to a “bad reputation” flag - Microsoft Q&A
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A
• I need to reset my mfa methods - Microsoft Q&A
• "We did not receive the expected response" error message when you try to sign in by using Azure Multi-Factor Authentication