I bought the UD-ULTCDL in February of 2020. I have it connected to 2 identical Dell U2415 monitors. Both monitors are connected to the docking station with HDMI cables. The set-up worked flawlessly until this week. Now the docking station doesn’t see the second monitor. I did what Mitchell suggested in this posted pasted below.
https://support.plugable.com/t/stopped-recognizing-external-monitor/18873
Thanks, Bob