Internal desktop app linked to OIDC enterprise app not able to SSO

Question

Hi,

We've an internal client app that is linked to an OIDC app in Azure that's used to leverage Azure as an IdP for sign-ins/authetnications.

However, this app has a lightweight browser of it's own built, so when it attempts to use SSO to sign the users in, it throws the standard Azure password prompt.

We have guessed it's something to do with the builtin browser and it not being configured to use the MS authentication servers or able to use the likes of the SSO extension you can get for Chrome.

Now the app vendor has said they don't support this as it's not something they've been able to figure out with other clients. They have basically said it's an Azure configuration, not their apps. Bit of a cop out on their part I feel.

Can anyone think of a way I can, I guess, force the client app to see the user who is attempting to sign-in is in-fact already authenticated and use that session?

Thanks.