I have read here that if a student incorrectly submits an assignment, that I cannot delete that assignment so the student can submit the correct one, as in Blackboard. Rather, the student can submit as many times as they'd like. However my students are claiming they are only being allowed to submit the paper once. I am using the plagiarism tool? Is this why? Also I only entered a due date, not an "until" date, which I left blank. Is this my problem?