Why does animation play in blend tree but not in transition?

Currently running Unity 2017.

Created an animation controller with a transition from walk (a blend tree) state to run (also another blend tree) state. The transition uses a parameter Speed and is triggered when Speed > 200.

Transition inspector window:
I use exit time of .97.
I have fixed duration check box checked.
Transition duration set to 0.25.
Transition offset 0.
Interruption source is set to none.
Ordered interrupt is greyed out but checked.

The run animation clip plays fine when I select the run state in the blend tree.

But when I select the play in the transition inspector window my character first walks, but when it comes time to transition to run, my character freezes.



What have I done wrong?

 

And what does the horizontal line I circled in red mean?