We have developed one custom app for Microsoft Teams that uses an external provider for authentication.

The authentication mechanism has been implemented as per the following documentation:

learn.microsoft.com: Use external OAuth providers

As per the above documentation, the use of deeplink has been suggested for redirecting the user to the app if it is not a web application.

return res.redirect(`msteams://teams.microsoft.com/l/auth-callback?authId=${state.authId}&result=${req.query.code}`)

The above implementation has been tested by the Microsoft Partner Center validation team, and it is working fine. If we are trying to use the custom app inside the Desktop Teams Client and Web Teams Client.

Problem:

If we try to use the custom app inside the M365 or Office context, then the user is redirected to the Desktop Teams Client (custom app) upon successful authentication.

The deeplink’s reference to the msteams://teams.microsoft.com domain is the cause of this.

Due to the above issue, the Microsoft Partner Center team is not approving our custom app.

Any help on this would be appreciated.

I was looking for some documentation which we can use for our reference but did not find anything.