The Noble Shaykh Saalih al-Fawzaan (may Allah preserve him) stated:
It is obligatory to preserve (the performance of) the prayer in congregation at Fajr and other than it. The matter of (over)sleeping is not always an (accepted) excuse. The one who is accustomed (to over) sleeping and leaving off the prayer is not excused. That which is obligatory upon him is to implement the means which will wake him up from sleep early. It is also obligatory upon him is to have the firm resolve to get up for the prayer.