Failed to verify the account using SMS with Error Code: 399287

Question

Failed to verify the account using SMS with Error Code: 399287

Charlie Rojo 65

Hi,

I have already raised a ticket (2509091420002402).

My old phone is defect and therefore I lost access to the email access and also to the Authenticator. I tried to set up a new phone, but I was asked to verify myself. Of course the authenticator method doesn't work. Outlook method also doesn't work. Therefore I only had SMS as the method, but using SMS, there is an error:

Error Code: 399287

Request Id: <Removed PII> Correlation Id: <Removed PII> Timestamp: 2025-09-15T07:03:56Z Flag sign-in errors for review: Enable flagging If you plan on getting help for this problem, enable flagging and try to reproduce the error within 20 minutes. Flagged events make diagnostics available and are raised to admin attention.

Even though my phone number is correct and I have used this method many times in the past. It failed. And I was prompted to reset my password, I did - which I should not have done, because with resetting my password, I still cannot access my email on the phone, and I also lost access on my computer... Now I'm completely blocked outside of my emails...

A side note, I cannot access my website host to add a TXT record, either, because it's also bound to my business email address, without access to my email I cannot log into the hosting backend.

How can I verify myself?

Now it's already been about a week and I still cannot access my Microsoft 365 business account. It's very frustrating because every time I have to go through the AI call agent to get to talk to a person, and this person would tell me that "today you will be contacted and get this solved", no progress, and my business activities are dependant on this email account...

So, please help urgently! @Anonymous

Charlie Rojo 65 Reputation points

2025-09-16T14:17:39.23+00:00

@Anonymous

Finally I managed to create a post... Please kindly have a look here. The ticket number is 2509091420002402.

Thanks a lot!
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T14:22:45.8866667+00:00

Hello Charlie Rojo,

Kindly share the affected email address, phone number, tenant ID and country name via private message.
Charlie Rojo 65 Reputation points

2025-09-16T14:25:36.2966667+00:00

I dont see where I can create a private message. Could you show me?
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T14:46:29.9833333+00:00

Hello Hin-V,

Here Charlie Rojo, already created a support ticket. I see you are again redirecting him to go with support ticket which he already did. I don't see that's the solution. Please change your answer or delete it if you don't have any other solution here.

Answer accepted by question author

Raja Pothuraju 47,835 Microsoft Employee Moderator

Hello Charlie Rojo,

Thank you for sharing your details via private message.

I’ve reached out to the engineering team regarding the MFA issue on your account. They have now unblocked it from the backend and cleared the bad reputation associated with it. You should be able to log in to the Azure Portal without any issues.

Please try signing in and verify if you can complete SMS authentication successfully. Let me know if you encounter any problems.

As a best practice, I recommend registering the Microsoft Authenticator method for your account instead of relying on SMS. SMS and voice call authentication methods are more vulnerable to IRSF attacks (telephony fraud) and are generally less secure.

For better practice, I recommend registering with Microsoft Authenticator method to your account instead of SMS method as these SMS/Voice telecom auth methods are susceptible to IRSF attacks telephony fraud.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

Charlie Rojo 65 Reputation points

2025-09-16T15:49:38.0966667+00:00

I can log in now, thanks a lot Raja! I wonder why it took so long with the normal support... I'd like to ask if this should be the normal way to ask questions here?

Yes, I had authenticator on my old phone, but it's defect... Now I'll register more phone with authenticator.

Out of curiosity, what is the "bad reputation" with the phone number and how it happened?

And also, there was a method of verification using Outlook, how should it work? It never works for me...
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T19:17:41.5766667+00:00

Charlie Rojo - That's great to know and I'm glad that I am able to help you out on this issue.

Regarding support ticket that's not normal. It varies depending on the engineer approach and sometimes it may also land in different queue. Due to that such scenarios occurs. But Q&A you'll be having border view by MVPs, Moderators, Community Champs.

You'll get this bad reputation when you have entered incorrect OTPs multiple times at the time of MFA verification.

Outlook email verification method will only be possible for Microsoft Personal Accounts (MSA) when they enable Passwordless login.

1 additional answer

Your answer

Charlie Rojo 65 Reputation points

2025-09-16T14:17:39.23+00:00

@Anonymous

Finally I managed to create a post... Please kindly have a look here. The ticket number is 2509091420002402.

Thanks a lot!
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T14:22:45.8866667+00:00

Hello Charlie Rojo,

Kindly share the affected email address, phone number, tenant ID and country name via private message.
Charlie Rojo 65 Reputation points

2025-09-16T14:25:36.2966667+00:00

I dont see where I can create a private message. Could you show me?
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T14:46:29.9833333+00:00

Hello Hin-V,

Here Charlie Rojo, already created a support ticket. I see you are again redirecting him to go with support ticket which he already did. I don't see that's the solution. Please change your answer or delete it if you don't have any other solution here.
Charlie Rojo 65 Reputation points

2025-09-16T15:49:38.0966667+00:00

I can log in now, thanks a lot Raja! I wonder why it took so long with the normal support... I'd like to ask if this should be the normal way to ask questions here?

Yes, I had authenticator on my old phone, but it's defect... Now I'll register more phone with authenticator.

Out of curiosity, what is the "bad reputation" with the phone number and how it happened?

And also, there was a method of verification using Outlook, how should it work? It never works for me...
Raja Pothuraju 47,835 Reputation points Microsoft Employee Moderator

2025-09-16T19:17:41.5766667+00:00

Charlie Rojo - That's great to know and I'm glad that I am able to help you out on this issue.

Regarding support ticket that's not normal. It varies depending on the engineer approach and sometimes it may also land in different queue. Due to that such scenarios occurs. But Q&A you'll be having border view by MVPs, Moderators, Community Champs.

You'll get this bad reputation when you have entered incorrect OTPs multiple times at the time of MFA verification.

Outlook email verification method will only be possible for Microsoft Personal Accounts (MSA) when they enable Passwordless login.

Answer 1

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