Emergency Help

Dears 

Kindly Your Experience to Provide Solution For Below Contiguous Case 

from 25 days Some one From Our Company Tried Backup Exec 2014 as trial and make backup over tape then cyber attacj happened erase all Server even backup exec server now we make new installation of one server and install backupexe then try to restore it say in restore server not trusted and ask for credential and dont know what credential 

so can help to restore without this password or what suggestion