Referees are humans an humans make mistakes all the time. Mistakes in matches were very rampant untill VAR came into the picture which reduced the mistakes.
Yet still, mistakes do happen because certain decisions they take on the field are to their own discretion but later, alot of football fans and analyst claim the referee was wrong. Example when there is in incident in the penalty box, the referees watch the video several times before taking decisions to their own discretion.
It's once in a while that referees don't make mistakes.
Referees will only not make mistakes when such incidents don't happen.