Third Monitor does not work through Dell D6000 dock

[JFK8]

I have a Dell D6000 dock, with 2 monitors attached via DisplayPort.  This setup works fully when my Omen is docked to the D6000.  I have added a third monitor, connecting via HDMI to the D6000 dock. 

When I do this, it is not detected by my PC, nor does the monitor recognize any signal as coming in.

I have tried restarting several times, and have checked for all drivers I can find online, including using the HP Support Assistant.  When I connect another laptop to my dock, the third monitor works as normal. (The other laptop is a Dell Precision 5570).  From this I know the dock, monitor, and cabling are all good.

Please help me understand what I am missing to enable a triple monitor setup on my Omen

[Huffer]

This is probably a limitation of the video system in your laptop. For an experiment, what happens if you try to connect via HDMI directly to the laptop?

[JFK8]

I have plugged the third monitor into the HDMI port on the laptop, while the other two monitors remain connected via DisplayPort to the D6000 dock.

This results in all 3 monitors working as expected.  So the laptop is clearly able to handle this many video displays, but it doesn't work when connected all through the dock.  Again, connecting another laptop to the dock will power all 3 monitors just fine.

[Huffer]

The devil is in the details. Its not just that the laptop will drive 3 monitors, its whether the USB-C Thunderbolt port can drive two DP monitors and an HDMI monitor. The dock can allow a third monitor connection but only at 30 hz which is not a very good refresh rate and will likely give you very choppy video. What is the other laptop so we can compare hardware? 

[JFK8]

The other laptop is a Dell Precision 5570

[Huffer]

Also with a USB-C Displayport port and Thunderbolt ports. The Dell is a workstation type laptop, which tend to be more capable than consumer laptops. The Dell is designed for video production work like CAD where more than 2 monitors are normal, even common. 8 gigs VRAM vs. 4 in your laptop. Its all a matter of how much video bandwidth the engineers allocate to the Thunderbolt port. I assume the two DP connected monitors are 4K? How about the HDMI monitor? I suspect if you connected two lower resolution monitors to DP you would get the Omen to display on all 3. It just does not have enough bandwidth to drive all 3 monitors while the Dell does. I do not think it is because the laptop is HP and the dock is Dell. 

[JFK8]

All 3 of my monitors are the same 1080p SCEPTRE monitors.  They are not high resolution, and I thought this laptop was Thunderbolt 3 compatible, which should be able to drive 3 1080p monitors easily.

[Huffer]

I agree you should be able to drive 3 HD monitors. I am aware of no adjustments you can make. I have several laptop/dock/multiple display combos in my office and occasionally run into this and have pretty much learned it either works or it does not. 

[Jupitero]

Hello.

I took a look at the Dell Universal Dock D6000 User Guide.

How did you connect it to your laptop?

If you are using it with USB-A port, then you are restricted to just 2 monitors.