So strange !!! my application has been withdrawn

Hi guys! I’m an international student. I applied to Drexel University as undergraduate for fall 2015 through CommonApp. I got an email from Drexel 4 days ago that all my application materials have been received and sent to admission team. Yesterday I got an email that my application was withdrawn. They didn’t write any reason. I’m really freaking out about this. It’s Sunday today and tomorrow they won’t work, I can’t call them.

Does this happen to anyone? Or does it happen to international students sometimes? What are the reasons? I know application can be withdrawn for not sending some documents or scores on time, but I did sent everything on time and made sure that they received everything.