Minecraft Services returns 403 "Invalid app registration" for approved Xbox developer application

Hello,

I am developing a personal, non-commercial third-party Minecraft Java launcher named PolarX.

I have registered in the Xbox Developer program and completed Partner Center registration.

Current configuration:

• Application (client) ID: 1e4a2da5-dc9d-4b33-8a46-7e849da21056
• Directory (tenant) ID: 555aed9d-1678-4d5e-afae-cee900a4664b
• Seller ID: 97223180
• Public client flows: enabled
• Redirect URI: http://localhost
• Supported account types: any organizational directory + personal Microsoft accounts

Microsoft OAuth, Xbox Live user authentication and XSTS authorization all succeed.

However, the Minecraft Services endpoint returns:

POST https://api.minecraftservices.com/authentication/login_with_xbox

HTTP 403

{

"path": "/authentication/login_with_xbox",

"errorMessage": "Invalid app registration, see https://aka.ms/AppRegInfo for more information"

}

Could you please advise how to register this application for Minecraft Services access, or provide the correct application/allowlist process?

Xbox Developer Program approved

Partner Center Seller ID: 97223180

Thank you.