U2515H, HDMI, not working

Hi,

So I just built a new computer with a i7-8700 processor on a Z370M motherboard with an onboard HDMI out port. I am using an HDMI cable to connect to the U2515H. It worked a couple of times but intermittently would show the "No HDMI (MHL) Cable" error message, until now. When it does not work at all anymore. I have tried to disconnect the power supply and all video cables and restarted my PC but none of it works. On the other hand, my DP port to mDP connection for my laptop works perfectly and flawlessly fine. Is there a way to fix the HDMI connection?