Keep in mind of different types of video cables. We can confirm that our Type-C Adapters are only compatible with the HDMI to HDMI connection with a 1.4 or higher HDMI cable.
DVI, VGA, and other additional video connections require a different adapter and will not work with our Satechi Type-C Hub Adapters.
Please note the different video cables in our Comparison Chart:
Q: My laptop has a Type-C with thunderbolt, but the HDMI doesn’t work. Will the HDMI work if the Type-C port supports thunderbolt?
A: Most of our Type-C adapters do not work with PC computers. The HDMI feature may be supported if your laptop supports DisplayPort over USB-C with Alternative Mode.
Q: What can cause a flaky external display when using the HDMI port?
A: Flaky connection can be caused by the connection or the HDMI cable. Also, please try to adjust the <sleep mode> on your computer settings to ‘never’.
On a Mac:
Please go to System Preferences > then select Energy Saver. https://support.apple.com/en-us/HT202824
By adjusting the "Computer Sleep" to never, it should resolve the flakiness in your HDMI connection. The Display Sleep shouldn't affect the Hub in any way.