is it a new monitor? or a new gpu?
Try switching ports and inputs(hdmi for dp or vice versa)
If its DP check is it is well connected. press the cable until its firmely secure.
Also check if the monitor is recognizing the right input. If its not auto detect you have to switch between inputs( hdmi or DP). My monitor is manual for eg.
I had similar problem when got a new monitor and it was faulty gpu. The displayports didnt work. It worked well when connected with hdmi(but no gsinc) but when i switched to displayport, got the same as you ‘No Signal’.
Hope this helps