Laptop docking station power supply does not work

I have 2 different power supply bricks that do the same thing,

Plug them in to an outlet, blue light on the power supply comes on as expected,

plug it in to the docking station, no power, and the blue light on the connector end goes off,

unplug from the outlet, and re-plug, and the blue light comes back.

This is getting very annoying as I support over 200 people at this office, replaced docking stations, and power supply bricks, but cannot narrow the problem down to anything other than Dell stuff just ***.