Bright white light/orb in sky

Picture above as reference

Time: 21:14 (local time)

Country: Czech Republic, near border of Poland

Weather: only stratosphere feather clouds

The light turned off and on in 2? Seconds interval
It lasted for 30 second, I was near a house on grass.
It was brighter than other stars in the sky

by Jaguar_EBRC_6x6