DisplayPort input won't work after disconnect while PC was on

[dokiduck343]

After disconnecting my monitor (Dell S2417DG, using DisplayPort) while the system was running, my monitor now will not display using the DisplayPort input. I thought I may have fried my GPU (gtx 1070) but it still outputs to the same screen via HDMI. What have I fucked up here?

EDIT: I factory reset and unplugged power to the monitor, this has fixed the issue

 

[helpstar]

Please post another answer with the solution, so we can mark that as solved