Input Axis Vertical is not set up?

I am new to unity and was using a tutorial on making 2d platformers. All was going well until this popped up: UnityException: Input Axis Veritcal is not setup. To change the input settings use: Edit -> Project Settings -> Input playerControls.Update () (at Assets/2D Mario Assets/Scripts/playerControls.js:66)

Im not sure what it means but I did go into the Input settings and I changed it to use the up and arrow keys for positive and negative buttons, but it still doesn't seem to register the inputs.

Im trying to get the character to jump with the up button, but it only goes up while pressing the left or right arrow keys.

Why is this happening and how can I solve it?