From Aug. 25, the mail service system changed to Outlook. Users cannot enter their mail with Povis app anymore, and they have to download Outlook app to access to mail on their mobil phone. It sounds sudden but it was already announced on Povis Bulletin Board. The new mail system starts with an empty mailbox. If users want to  access to the former mail, they have to go to "oldmail.postech.ac.kr."
Also, users can use "office 365" with "onedrive" through Outlook so that they can share files and work simultaneously with other users online.