Welcome to the Forum. 
That might be the general cause for your problems? Starting doing shows with a not properly set configuration will hardly work most times 
So let’s see how we can help you:
In the mAirlist configuration → Audio Routing
That’s the configuration that can be opened independently from the mAirlist playout, additionally to the link in the playout window.
You can find it in the windows start menu folder of mAirlist (and should pin it to the taskbar).
Why are there two ways to open the configuration?
Please take a look here and maybe translate it with google:
Nah Either you didn’t set the Audio Routing correctly in mAirlist or the microphone wasn’t setup/connected properly to the mixer.
mAirlist will only recognize the USB device in whole and not the attached microphones or line-in hardware. So it can’t “not accept” a connected device separately.
What to re-arrange? The layout? Or the tabs to display Playlists, elements etc?