Custom App on Teams not showing on Desktop App

[obrown8]

I have created a custom teams app through app studio that links to Outlook.com so users can view their inbox without leaving teams. The webpage loads fine on the Teams web app but not on the Teams desktop app. Any suggestions on getting this working for the desktop app?

[#2]

@obrown8 Teams desktop is blocking the outlook URL in tabs due to authentication, in web you are already logged in that why it working in teams web. You need to implement auth for your Tab. Please look at Authentication in Tabs