Error 40901: Phone number locked in Microsoft 365 Developer Program

Question

I cannot join the Microsoft 365 Developer Program because my phone number is locked with error 40901.

Please delete my existing Developer Program profile associated with my phone number.

MS-CorrelationId: [Moderator note: personal info removed]

Answer 1

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Hi Mayumi Sakagami

The 40901 error usually indicates that the phone number is still associated with a previous or inactive Microsoft Developer Program account.

As a forum moderator, I do not have access to backend systems to view or unlink phone numbers from existing developer profiles.

The Microsoft 365 Developer Program now enforces a one-phone-number-per-account policy. Even if the original account was deleted, your mobile number may still be linked to the old developer tenant, preventing reuse for a new signup. 

• If you recall the old account, you can try logging into the Dashboard - Microsoft 365 Dev Center using the old account originally linked to this number. From there, select Delete Profile to remove the old account. After deletion, the system may take up to 60 days to release your phone number so it can be reused for a new registration. 
• If you no longer have access to the old profile, I recommend contacting Microsoft Developer Support through the following link: Services Hub. Please note that this portal (Services Hub) is a paid ticket and access is subject to certain conditions, which you can review here: Services Hub sign in FAQs | Microsoft Learn.
• If you need to create a new developer account right away, you might consider using a different phone number to complete the registration process immediately.

Kindly let me know how you get on, as your feedback can help others in the community facing the same problem. 

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Answer 2

Deleting or unlocking a Microsoft 365 Developer Program profile that is locked to a phone number cannot be done from documentation or forums and requires direct handling by Microsoft.

From the program rules:

• Only one Microsoft 365 Developer Program account can be associated with a single phone number.
• To set up a new Developer Program account with the same phone number, the existing Developer Program profile must first be deleted from the Developer Program dashboard by signing in and choosing Delete Profile.

Because sign-in is blocked in this scenario and profile deletion cannot be performed on behalf of a member, the only supported path is to contact Microsoft support so they can review the account status and assist according to the program’s terms and conditions.

Actionable steps:

1. Try to sign in to the Microsoft 365 Developer Program dashboard with the account currently tied to the locked phone number and, if access is possible, choose Delete Profile to release the phone number.
2. If sign-in is not possible due to the lock or error 40901, contact Microsoft support (for example via standard Microsoft account/Office 365/Microsoft 365 support channels) and provide:
   • That the issue is with the Microsoft 365 Developer Program.
   • That the phone number is locked with error 40901 when trying to join.
   • That the phone number is already associated with an existing Developer Program profile and needs to be released or the profile deleted.
3. After Microsoft confirms the old profile is removed and the phone number is released, return to the Join the Microsoft 365 Developer Program page and sign up again with a supported account type (work account, Visual Studio ID, or Microsoft account; not a phone number or *.onmicrosoft.com address).

Note: Program policy allows only one Developer Program account per phone number; any new account using the same phone number is only possible after the previous profile is deleted and, if applicable, after subscription age requirements (such as the 60‑day condition) are met.

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References:

• Microsoft 365 Developer Program FAQ
• Welcome to the Microsoft 365 Developer Program