In CreateWithCode unit 3, player jumps at start but hangs in the air

I am learning the Create WIth Code 2 unit 3, but my player hangs in the air after the step to have him jump at start.
UseGravity is on, and I found I had to add the rigidbody component to the construction worker I chose as the player. But still, he stays in the air.

The box collider went well below the player, so it collided with the ground before the player landed.
I reset the box collider to have y=1.5 and y size 3 and the player now jumps and lands on the ground again.
Should have remembered this problem with the feeding the deer game.