Unity Lobby Error - When testing inside Unity tool

I created a simple networked game and followed the Networking documentation to create a lobby scene and then my game scene. I have so far, been testing outside of the unity development environment. Today, I tried to run the game - both clients on the same machine - one inside unity and one out.

However, when I run the game inside the Unity environment, I hit the LAN Host button on the built in Network Hub in my lobby scene, and instead of waiting for other clients to join, the app jumps...

Unity Lobby Error - When testing inside Unity tool