Ps4 suddenly shows no signal on the monitor?

Moin people, after 2 weeks pc time again my ps4 connected to the monitor and noticed that suddenly no signal comes through. Everything used to go smoothly. As soon as I mimic the ps4 the monitor jumps but no picture comes but the error message: no signal. On other TVs, it works strangely. Did the PS4 already started in safe mode but even there's no picture through. As I said two weeks ago, everything went smoothly. Would be cool if I could help jmd. (And yes, unfortunately, I currently have only the monitor with which I can gamble otherwise I would have long since connected a TV.)

Have you ever checked the settings on the monitor?

Yes