Monitor Help

[hoiv]

Hello, so I have to asus VG248QZ monitors, and I bought 2 Display Ports with them. Only 1 of them will work. I unplugged the second monitor, connected a HDMI, and it worked, but, I want to use this extra display port. I don't know if I can even do that, but that's why I am here. Also, on my second monitor (the one connected to the HDMI), only goes up to 75 Hz, and not 144 Hz (when both monitors are 144 Hz). It says "Out of range" on my monitor when I try and turn it up to 144 Hz. I don't know if my GPU simply can't handle it, or what the problem is. I have GTX 970. Help please.

[narrdarr]

I think hdmi can only do 120hz