No display on HP Elitedisplay E231 (Displayport)

I can't seem to make my HP monitor work as a 2nd display for my Macbook Pro's (2020) displayport. At first I only had an HDMI cable and usb c hub that has hdmi port in it so I bought a displayport to hdmi adapter. Then I bought a usb c to displayport cable so I didn't have to use adapters - still didn't work. I've tried the cables and adapters on my desktop computer/monitor and they're all working. Is it possible that the displayport of the monitor is the culprit here? Meaning it's not working already? I've bought it second hand on a reliable source and they said that they've tried the monitor before selling them. Or do I really have to try and use the other ports (dvi or vga)?