Beamer Picture / Video goes out or Has interference when I turn on / off, why?

I have a projector on the ceiling and it goes an HDMI cable through ceiling and wall about 5 m long to HDMI flush-mounted box. Next to it are 2 x socket where I connect my laptop. When I turn light on / off, it has glitches for a few seconds, so go off and on again the picture or video. I have only 4 LED lights except. Why? What should I do?

Why? -While you press the light switch!
Have you ever thought about replacing the LED lights?
Alternatively, cables and cans of HDMI and power as far apart as possible apart.
Apparently the switching ensures an interference pulse.
Alternatively interference suppression magnet to beamer cable.
Other alternative: Take HDMI cables that are better shielded against interference.

The sockets are on distance.

Probably a cheap cheap HDMI cable with inferior shielding installed (against interference, such as switching power supplies in LED transformers / -Leuchtmittel).

There are differences in quality, which show up especially when you use longer cable lengths.

Here explained: https://www.welches-hdmi-kabel.de/unterschiede/

Times try a better HDMI cable. Possibly. Can also an additional sheath wave filter (there are also individual), close to the HDMI outputs mounted on the cable, help.

https://de.wikipedia.org/...llenfilter

PS: Switching power supplies generate noise on the 230V ~ line network!

Many Thanks. You have helped me a lot

LED gas lamps have a crazy inrush current, so around 50A each. That's just 200A short, but still there! Since the mains voltage works together briefly. Try it with another brand, did not lend the not so high inrush currents.