Dell Vostro P88G with Ubuntu 20.04 - second external display stopped working

Hi guys,

Initially I had a working setup of two working external displays, one connected via HDMI and a second connected via usb-c connected to an adapter of usb-c to Display Port and finally connected to the second display using a Display Port cable.

After a couple of weeks (and probably some Ubuntu system updates) I started to realize that the second display is only working when the HDMI was not connected with no apparent reason. Now I realized (after using only the first display for a while) that when I connect the second display it doesn't work at all even when connected all by it self. The screen says that there is "No DP signal from your device".

Who can help me solve this?