External mike with Scarlett 2i2 doesn’t record

I’m brand new to Audacity. Used the “Built-in Mike” on Mac OSX 10.9.5 and works fine.
Hooked in Scarlett 2i2 with mike to USB and doesn’t record. The mike button says (“Unavailable, use system mixer”).
See screenshot.
Went to Mac>>System Preferences>>Sound>>Input>>Scarlett 2i2 and it says “The selected device has no input controls”.
What to do???
Hong Kong
Screenshot 2018-08-11 17.37.58.png

It’s normal for a USB connected device to have no volume controls in Audacity. Does your microphone work if you plug headphones into the 2i2?

Also, the 2i2 is natively a stereo device and works best if you have stereo selected in the Audacity toolbar. Do you? What are the settings behind the yellow message?