Acer Aspire E17 screen always goes out?

On my Acer laptop, the screen goes on and off all the time. If I do not move the mouse it fades away, but if I then move it or press buttons, it goes on again as if it had not been (no standbys, menu etc remain or even programs)
What could be the reason?

It could be due to the adaptive brightness.

So you could change it:

For Windows 10

In the search field, enter settings.
Tap or click the Settings entry (trusted Windows Store app).
Tap or click System.
In the category Screen you will find the option Adjust screen brightness automatically.
Tap or click the slider to toggle the option on or off.
Tap or click Apply.
Close the system window.

For Windows 8 (8.1)
If you use the modern Windows interface (Windows Modern User Interface (MUI)):

Swipe from the right and touch Settings.
Touch Change PC Settings.
In the PC Settings screen, tap PC and Devices.
Touch Power and Power Save Settings.
At the top, a gradient slider is displayed. Slide the slider to Off to disable Adaptive Brightness.

If you use the traditional Windows desktop:

Tap and hold the launch button to open the Apps screen, and then tap Control Panel.
Touch Hardware and Sound.
Tap Change power plan settings.
Tap Change advanced power settings.
In the advanced power settings, tap the + next screen to display the options.
Locate the setting to enable Adaptive Brightness and set the setting to Off.

If that does not work then you could find something under the Intel graphics settings.

You can right-click on a blank space on the desktop and then go to Intel Graphics Settings.