Azure Static Web Apps GitHub OAuth integration fails with HTTP 400

I cannot connect my GitHub account to Azure Static Web Apps through the Azure Portal.

GitHub authentication succeeds and displays the message that my account has been successfully authorized. However, the Azure Portal fails to complete the connection.

The following request returns HTTP 400:

POST https://functions.azure.com/auth/github/generateCreateAccessToken

Response:

{"statusCode":400,"message":"OAuth authorization was denied or malformed."}

The browser's CORS preflight request (OPTIONS) succeeds with HTTP 204.

Troubleshooting performed:

Tested regular Chrome and Incognito mode.

Confirmed that my GitHub primary email is verified.

Revoked and reauthorized the Azure App Service Creates OAuth application.

Confirmed that Azure Static Web Apps does not appear separately in my authorized OAuth applications.

Azure reference ID:

20261108T121111Z-1845ddfb849mw6cchC1RIOgq000000001g600000000018xg

Could someone from the Azure Static Web Apps team clarify whether this is a known issue with the GitHub OAuth integration or an Azure-side token exchange configuration problem?

Thank you.