Microsoft 365 Developer Program GitHub account linking returns 404

I am using the Microsoft 365 Developer Program at developer.microsoft.com.

When I go to My settings and try to link my GitHub account, the official GitHub OAuth authorization flow returns a 404 page, so the GitHub account cannot be linked.

I tried different browsers, private/incognito mode, clearing cookies, logging in to both Microsoft and GitHub first, and restarting the linking process from the Developer Program dashboard.

I also tried creating a support request from the Microsoft 365 admin center, but the Support Assistant keeps routing the issue to Power Platform support, and no service request is created.

This appears to be an issue with the Microsoft 365 Developer Program portal or its GitHub account-linking OAuth endpoint. Could someone from the Microsoft 365 Developer Program team check this or advise how to create the correct support request?

Update:

I checked GitHub Settings > Applications > Authorized OAuth Apps, and there is no Microsoft-related authorization listed.

I also inspected the failing request in the browser Network tab. The 404 happens on the GitHub authorization URL itself, before the flow reaches the Microsoft callback endpoint:

https://github.com/login/oauth/authorize?client_id=c027f9e6052f86427ac2&redirect_uri=https://developer.microsoft.com/en-us/microsoft-365/profile/settings/accounts-linked?accountType=GitHub&state=[REDACTED]

This suggests the OAuth flow fails before GitHub authorization is completed, possibly because the GitHub OAuth client_id used by the Microsoft 365 Developer Program portal is unavailable or misconfigured.