My Discussion assignment got locked on an earlier date (06/08) than the due date (06/12) or the end of the available dates (06/05 - 06/15). I also checked Module's "Lock until". The Module was set to Lock until 06/05. So, it should be unlocked by now (besides, students were submitting posts with no problem, until it got locked on 06/08 by 11:59pm, which means Discussion assignment was available to students and it got locked suddenly before the end of the assignment). I also checked "Close for Comments" and "Open for Comments" options. This cannot be the problem, because these options appear after the due date. The due date is 06/12, and my Discussion assignment got locked on 06/08. So, how can I unlock this Discussion assignment?