This is caused when your Windows operating system has a setting disabled that prevents your monitor listing available resolutions that it doesn't support.
If your display is stuck displaying "No Signal" when a client has tried to connect to you, follow these steps below.
1. Plug in a second monitor or a TV that supports HDMI Input
2. Open your Windows 10 settings menu -> select System -> Display.
3. Highlight the monitor (by clicking on it in the settings) you believe to be broken (It will either be numbered 1 or 2).
3. Click "Display adapter properties" at the bottom of this page.
4. Click the tab called "Monitor"
5. Click the checkbox "Hide Modes that this monitor cannot display"
(Please note: On my PC this check box is greyed out, but you should be able to select it)
6. Click Apply and OK
7. The monitor should be now only be able to be set to resolutions supported by the monitor
If it does not fix it, please reach out to support.