I had a session with support and they suggested asking this here. Basically we have several apps that can "call out" to Outlook and will pre-populate an email and possibly include an attachment. The problem we are running into is unless you've launch Outlook previously on the server and signed in, the process kind of falls on it's face trying to load/configure Outlook. I've also seen similar experience with OneDrive and trying to save documents there. Our current Workaround: Assist users to sign into server(s) via RDP, launch and sign into Outlook/OneDrive. After doing this, the user can access email or OneDrive in their RAS session. While this technically works, it feels like a lot of added steps and becomes a bit tedious when you ramp up the user count. Also becomes a hassle when passwords are changed/reset. One other potential workaround I plan on testing is scoping these M365 apps in RAS and sign in to those that way.