What is the ruling on Fajr prayer performed in the Maghrib before true dawn, when the time for it has not yet begun? And what must be done in this situation?

The Fajr prayer is not valid except after the appearance of the true dawn, which spreads across the horizon, by scholarly consensus. For those who cannot ascertain the entry of the time by observation, they can follow a trustworthy muezzin or rely on a reliable calendar. It is not correct to say that the majority of Muslims pray Fajr before its due time, as most of them rely on calendars or delay the prayer for a sufficient time to ensure the entry of the time. Prayer performed before its time is invalid and must be repeated. Prayer is not permissible except with certainty or a strong presumption that the time has entered. If a Muslim is certain that the prayer is being performed before its time, he should pray in another mosque that delays the prayer. If he cannot, he should follow someone whose knowledge he trusts, such as a trustworthy muezzin or reliable calendars.