I followed all the advice about settings but have been unable to get Audacity 3.0.2 to record uTube music playing on my Windows 10 computer (model ASUS ZenBook Flip 10). Previously, on a Windows 7 computer, I had no problems recording. I used the following settings: WASAPI, microphone array Intel for digital, stereo recording channels, and Speakers RealTekR Audio. What can I do to make this work? I would prefer not to leave Audacity and find another application.
Use [u]WASAPI (loopback)[/u] and choose the loopback device to match the device that’s actually putting-out the sound.
I used the following settings: WASAPI, microphone array
That would be the microphone built-into your laptop… Not what you want. 
Use “WASAPI loopback”.
See: https://manual.audacityteam.org/man/tutorial_recording_computer_playback_on_windows.html