GarageBand is not recognizing guitar signal through Focusrite on my Mac

Hi, my GarageBand sees just fine Mic, connected via Focusrite, but signal of guitar doesn't come through. Signal comes to the input on Focusrite - light blicks green, I've checked several cables, but still- no luck.

When I test if signal comes to computer (settings - sound - scarlet usb) - computer recognises the signal, scale is moving.

Monitor is on. Sound is on. But still - guitar signal doesn't show up.

[Re-Titled by Moderator]

Original Title: No guitar signal