Help with Blue Laser Use

I tried to use the blue laser this afternoon (Tuesday) as well, and the machine is moving as expected but the laser is not being produced. I’m also new to the machine, but did successfully engrave a few times last week. Using the same settings as last week, the laser is now not being produced. I tried turning off and on a few times, and still no laser. Is there a specific setting/button that needs to be checked to ensure the laser is produced?

This is surprising given the laser discussion yesterday, which seemed to indicate the blue laser was working fine.
(yesterday’s discussion here:
Laser's - what's working?)