HTTP ERROR 401 must authenticate

URI:/service/home/teacher@mail.g177.ru/Briefcase/%D0%94%D0%BB%D1%8F%20%D1%83%D1%87%D0%B5%D0%BD%D0%B8%D0%BA%D0%BE%D0%B2/%D0%96%D1%83%D1%80%D0%BD%D0%B0%D0%BB%20%D0%9A%D0%BB%D0%B0%D1%81%D1%81-%D0%95%D0%BA%D0%B0%D1%82%D0%B5%D1%80%D0%B8%D0%BD%D0%B1%D1%83%D1%80%D0%B3
STATUS:401
MESSAGE:must authenticate
SERVLET:UserServlet