RDP ipad troubleshooting - won’t connect outside of home Wi-Fi despite have remote access tunneling

I’m able to connect to my computer within my home network via RDP.

Once I leave the network and use cell service via my iPad, i can’t access the computer.  BUT with the same credentials, tunnelling etc i can access the computer via my MacBook Pro via Microsoft RDP - so one would think the ports aren’t blocking entry to my home network.  

I’ve updated my IOS and App to the latest version….no change.  I’ve seen both error 0x204 and 0x4.  Shortly after, i go back to Wi-Fi in my home network, and test the same RDP script file works fine.

Any thoughts as to what could be happening?