Monitor is not receiving Hdmi signal?

I have the following problem, I bought a gaming monitor from Acer and it is also a fairly new monitor. The monitor is used to play on the pc or to play on the ps4. Everything works great on the pc, but if I want to play ps4 and switch on the monitor then "No signal" is displayed. If I disconnect the monitor from the power while it is in operation and plug it back in and then it starts up, the hdmi signal is there. Why is that can someone help me?

I think the native resolution has something to do with it, but now I don't know how you could change it (on the playse maybe?)

Maybe just restart the PC.

Or there's usually an input switch. Maybe you should see if it is set correctly.

Everything works great on the PC, it doesn't even run through Hdmi. There are only problems with the HDMI signal. When the monitor is switched on and there's "No signal" I disconnect it from the power and plug it in again, then the monitor starts up and then it transmits the Hdmi signal and the ps4 then displays an image. But in the long run that's not a good thing if the monitor is disconnected from the power each time it is on

I just don't understand why I don't get a signal every time the monitor is switched on normally and when I then disconnect it from the power and it starts up, the signal is there but the problem is only with Hdmi.