The Host Emulator navigation bar includes a Start/Stop toggle button. Clicking Start opens all models configured to automatically start and then causes all open models to listen on their specified TCP ports for connection requests. Clicking Stop closes all models, which disconnects all sessions connected to the Host Emulator and causes all open models to stop listening for connection requests. If a client application attempts to connect to a model while it is not listening for connection requests, it will receive a "Connection refused" error message.
Note: Do not have more than one model listening on the same TCP port
at the same time for connection requests. If you have configured more than one
model to use the same TCP port, make sure only one of them is open at a time.
The best way to ensure this is to not configure these models to use Auto Start.