Possible reason? Wife's EAD denied

Just checked USCIS online status and found out wife's EAD denied.
Really a shock!

My wife applied i765 (EAD) two months. She has not been out of status, and my 485 has been pending for almost a year.

The notice is still in mail and I can't figure out why it's denied?

Any possible reason, anybody can shed some light?

Thank you thank you thank you.