Cannot hear left track while recording

cannot hear left track in headphones when trying to record right track. I should hear both tracks to play (right) guitar in-time with left rhythm
Have Sure SRG240A headphones
Have Roland GR-55 into a Focusrite scarlett 212
into A Toshiba laptop with 10GB ram and 500GB SSD
Settings are MME, Focusrite, stereo, Focusrite

Are your headphones plugged into the Focusrite?
Are you able to hear normal playback from Audacity?
Which version of Audacity are you using? (look in “Help menu > About Audacity”).