Error 40354 when creating Microsoft 365 Developer Sandbox

Question

I have an active Microsoft 365 Developer Program benefit on my work account.

When I try to set up the sandbox, I get:

"Your request has been rejected because some of your information is invalid."

Code: 40354

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

I am using my work account where the benefit is active.

Can you help?

Answer 1

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Hi @VK

[Solution updated 25/03/2026]

Make sure to use the admin account credentials (automatically created when you first signed up) to set up Sandbox.

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Can you clarify how do you get the benefit on your work account?

Based on my research, I saw some users also encounter the similar behavior as yours. At first, it will return error code 40354, after a few attempts, it will return with the message "Your phone number is associated with an existing developer account."

Could you please double check if your phone number was previously used to register with another tenant?

Could you also provide a screenshot at what step you are stuck via private message?

I look forward for your reply.

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