While running a test print my extruder begins to click and the filament stops extruding.

I am using a Prusa IV3 12" with the following:

1.75mm Hexagon Hot End
Printing PLA at 210*c
Bed at 60*c
Slicing with Simplify 3D

While printing, the first 5-7 layers will print just fine and then the extruder begins to click like the hobled bolt is having a hard time grabbing the filament.

Any ideas?