[NAME]  The XPS 15 9500 is a DisplayPort HBR2 system, not an HBR3 system.  As indicated in the WD19S User Guide, when paired with a DisplayPort HBR2 system, your dual display maximum is 1920x1080 (technically 1920x1200, but Dell doesn't seem to account for that resolution anymore).  You don't have enough bandwidth to run dual 2560x1440 from that system through that dock.  So you have two options: I wrote an explainer post on the various operating modes of USB-C and Thunderbolt, including their impact on achievable display setups, over here if you're curious.
Hi,  I have bough XPS 15 9500 (Intel i9). I want to use WD19S docking station to connect 2 U2719D (2560x1440). I only want to use the 2 monitors. The laptop built in LCD will be off. Monitors are plugged in by DisplayPort directly to WD19S. I bought the WD19S to be able to plug in jus a single cable to my laptop. The problem is that only 1 of the monitors gets the native resolution (2560x1440). The second one gets 2048x1080 which is not acceptable. How to solve that issue? I require 2 monitors.   Regards
XPS 15 9500, WD19S, 2x U2719D 2560x1440