Login Prompt when requesting 3rd public API

[kemaltolga]

I have custom Tab app. I am able to get the Teams context. I've also implemented SSO, so all mgt components are working fine. 

I have a custom ASP.NET Core WebApi (v6). It does NOT require authentication. I've decorated the controller method with [AllowAnnonymous]. I've tested the endpoint in browsers and Postmost. All good. 

Back in my custom Teams Tab app, I make a request to aforementioned API endpoint. It looks like this:

https://localhost:44332/Test

As soon as I make the request, I get a popup to login.microsoft.com. Why? What am I missing?

Thank you,

Tolga

[#2]

@kemaltolga - We are looking into this I will get back to you soon.

[#3]

1.Are you using authorization in header section?
2.If Yes, In controller section if authorization is already present then ,Could you please remove the authorization section try it once?
3.Which document you refer for SSO Authorization?

[#4]

Could you please confirm if your issue has resolved or still looking for any help?