Answer: Because of the its assumption of earth being at the centre of the universe and also, its parallax argument.
Explanation: Geocentric model is the
theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the centre of it all. It was generally accepted until the 16th century, after which it was superseded by heliocentric models
Among many, geocentric model was considered because of its stellar parallax argument.
What is parallax? Parallax is the apparent change in position of objects due to a change in observation location
The ancient Greeks claimed that if the Earth is moving around the Sun then the stars should shift their positions due to this orbital motion (called stellar parallax). The stars don't shift. They don't shift enough for you to notice, but they do indeed shift. This is essentially the same reason the moon appears to follow you around when you drive - it's too far away for any apparent shift due to your motion.
