Teams Custom App - 401 Unauthorized for other Team Members

Good Morning,

I have issiue with my Custom App. I create very simple app just showing our SharePoint pined to left side bar. 

I can access this it, and SharePoint is showing, than nobody else in company can access it. They see the button but SharePoint is not loading or showing 401 Unauthorized error.

Did anyone face same issues? Is there any known solution for this situation?

Regards,

Michal