RDP Connections Failing to Connect

I’m experiencing an issue connecting to endpoints using RDM for iOS. I exported the .RDM file from Windows with credentials, and properly imported the .RDM via iTunes app sharing. All endpoints and folders are there and credentials are there. Using RDM, RDP fails. Using Microsoft RDP on same iOS device to any of my endpoints is working without issue. Pinging the endpoints in RDM is working. It feels like RDM is timing out too quickly when attempting RDP connections.

Note that I’m connecting over VPN, and Microsoft VPN works great. I do NOT have an RD gateway setup in Microsoft’s app. I tried to change those settings in RDM on iOS and no effect. I haven’t figured out how to get verbose logging in RDM or where to find it so I know more about WHY the connection failed. VPN is handled via iOS.

All of these endpoints are fine on Windows as well. Any thoughts on how I can troubleshoot this?