Dock external video troubleshooting and single thread

I can't get my DisplayPort to work. Dell Latitude E6520. The monitor is a Samsung  U28E590D. The Docking station is a A00. I updated my BIOS from A08 to A19 to try to get it to work. Graphics driver says it is up to date. Using a DP cable to a DP input on the monitor, but no signal is there. Tried two new cables.

Thanks, Jeff