Animation not working during gameplay

Here are the properties prior to getting it fixed:

Idle:



Walking:



Here are the transition settings:

Idle to Walking. Notice previewing transition was not available too




Walking to Idle:



The solution is rather simple, on Idle animation, change the speed to 1 (not working when the idle starts with 0):






After setting the Idle's speed to 1, the walking animation works during game play; and the animation transition and preview pane also become available in Inspector too: