The ruling on one who drinks after dawn believing that dawn has not yet appeared

Question:
On one of the days of Ramadan, I intended to fast. After that, I dozed off and woke up, and I heard the news on the radio, so I thought that the call to Fajr prayer had not been made yet. I drank some water, and I later found out that the call to Fajr had been made. Does this invalidate my fast?

Answer:
Yes, you must make up the fast. You must make up the fast, because you were careless, you did not take precautions, and you did not ask. Yes.