S2719DGF, not connecting after overclocking

Hi all,

I'm having some issues with my new monitor. Everything was working OK until I set the overclock. Then it stopped working. I have tried the full power off and reset but no change 

I can connect the new S2719DGF to my laptop over HDMI

I can connect my PC to another monitor over HDMI and DP

I cannot connect the PC to the new S2719DGF. When connecting it says scanning for input signal. Then no input signal found and it goes straight into power save

I'm out of things to try!

Any help is greatly appreciated