Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.
We have a troubleshooting tool that helps us find out what is going on in situations like this. Please plug the dock with your monitor attached to the 4K port into your computer, then go to this page and follow the instructions there:
When emailing us the diagnostics results please mention ticket “332260” in the subject.
Also, please be sure to use the included USB-C to USB-C cable as some third party cables may not properly support the ability to drive the 4K HDMI port.
Please don’t hesitate to let us know of other questions.
Thanks again for contacting Plugable support and best wishes!
Senior Engineer | Product Owner