Dell Display Monitor S2419H Message "No HDMI2 signal from your device."

Hi all, I am having trouble connecting my laptop (Dell XPS 15 9575) to the display monitor.  The display monitor usually comes on automatically when I connect my laptop to my Dell DisplayLink docking station. Today is the first time that I've gotten the message on the display monitor, "No HDMI2 signal from your device."  I've tried everything that I can think of, i.e. restarting my laptop, rebooting the display monitor, changing the display monitor to HDMI1, HDMI2 and Auto, tested my USB-C to USB-A adaptor to make sure that it is working fine, contacting dell support, etc... I bought all items from Dell at one time and they are less than 2 years old.  Any help would be greatly appreciated. Pleeeeeease and thanks in advance!!