D6000 dock, not connecting to display, #2

@IceDell 

I have a Dell D6000 Dock

It was working properly but yesterday suddenly it started to not display any connected monitors.

I tried following tests.
1-Updated display link driver.
2-tried different computer previously working good Dell Latitude and lenovo flex 14.
3-tried different connections HDMI/DP
4-Tried USB3.0 connection instead of Type-C

The laptops are working with direct connection to monitors.

Dock is working normal for other connections power/usb etc.

How can I resolve this? Is there a way to reinstall firmware (to test). Note that I checked with firmware updater and it verified that dock firmware is up to date.

Thanks