Can’t sign up for Microsoft Developer Program — Error 40901 & phone number already linked

Question

I am writing to request assistance with joining the Microsoft Developer Program. My goal is to create a Microsoft 365 E5 Developer Sandbox for learning and hands-on practice, allowing me to explore Microsoft products end-to-end.

I intend to use Microsoft 365 applications and services—including Word, Excel, PowerPoint, Outlook, Access, OneDrive, SharePoint, Microsoft Forms, and Planner—as well as Power Platform tools like Power Automate and Power BI, all under a single developer (learning) account.

However, I am unable to complete the signup process due to the following error:

“Your phone number is already associated with an existing developer account.” Error Code: 40901 MS-CorrelationId: [Insert your Correlation ID here]

It appears that my phone number (ending in 2156) is linked to an old or inaccessible developer account. my account is PII Removed

I kindly request your help to unlink or release my phone number from any existing developer accounts. This will allow me to create one Microsoft Developer account to access Microsoft 365 E5 products and Power Platform tools for educational purposes.

I have been trying to resolve this issue for over a week and would greatly appreciate your guidance and support.

Thank you very much for your time and assistance.

Kind regards,

Answer 1

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Hi 楊博宇 - 電機, 

Thank you for reaching out to the Microsoft Q&A Forum and sharing the issue you are facing. 

I fully understand the inconvenience of being blocked from setting up an E5 Developer Sandbox for your learning goals. Regarding the error code 40901 you encountered, this confirms that your phone number is currently associated with another existing Developer Program account (likely an old or inactive one). 

However, I can suggest the most feasible solutions for your situation: 

1. If you need to create an account immediately for your studies, the most effective method is to use a different phone number (such as a family member's number or a secondary line that has never been registered with Microsoft Developer) to complete the verification. This is the only way to bypass this error instantly. 

2. 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. 

As a forum moderator, I do not have access to internal data systems to intervene directly in profiles or manually unlink phone numbers for you. 

If the above steps do not work, you can contact Microsoft Developer Support via the Services Hub. However, please note that this channel often requires a paid ticket or specific enterprise conditions, which may not be suitable for individual/student needs. 

You can review here: Services Hub sign in FAQs | Microsoft Learn  

I hope this information clarifies the situation. Please let me know if you have any further questions. 

Thank you for your understanding and cooperation. 

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