Minecraft Services returns HTTP 403 "Invalid app registration" for my own third-party Java launcher

Hello Microsoft / Xbox Developer Support,

I am an independent developer working on a Windows desktop application called SH Launcher, a third-party launcher for Minecraft Java Edition.

I have already created my own Microsoft Entra App Registration for SH Launcher and implemented the authentication flow using the app’s own Client ID. The application is configured as a desktop public client with a localhost redirect URI and no client secret.

The authentication chain currently reaches the following stages successfully:

• Microsoft OAuth: PASS
• Xbox User Authentication: PASS
• XSTS Authorization: PASS

The next request to Minecraft Services fails at:

POST /authentication/login_with_xbox

with:

HTTP 403

Invalid app registration

This indicates that the technical authentication flow is working, but the SH Launcher App Registration is not currently authorized for Minecraft Services.

I am trying to follow the official authorization process and do not want to use another launcher’s Client ID, spoof an application identity, bypass authentication, or modify Minecraft’s normal session validation.

I attempted to investigate the ID@Xbox onboarding process, but the onboarding form requires a D-U-N-S number / registered business identity. I am currently an individual independent developer rather than a registered company.

Could you please clarify:

1. What is the current official process for authorizing a third-party Minecraft Java Edition launcher to use Minecraft Services?
2. Is ID@Xbox onboarding required for Minecraft Services App Registration authorization?
3. If ID@Xbox is required, is a registered business entity and D-U-N-S number mandatory for an individual developer?
4. Is there a separate Minecraft-specific application registration or approval process for third-party launchers?
5. Is aka.ms/AppRegInfo still the correct route for requesting Minecraft Services access? If not, what is the current replacement?

Technical details:

• Application: SH Launcher
• Platform: Windows desktop
• Client type: Public client
• OAuth redirect: http://localhost
• Microsoft OAuth: successful
• Xbox User Auth: successful
• XSTS: successful
• Minecraft Services /authentication/login_with_xbox: HTTP 403 Invalid app registration

I can provide the Entra Application (Client) ID, XSTS error-free evidence, request correlation IDs, or other non-sensitive diagnostic information if needed.

Thank you for helping me identify the correct official authorization process.

Best regards,
SH Launcher Developer