sudo mount -t cifs //cerndfs.cern.ch/dfs/ /mnt/cernShr/ -o credentials=/root/.smbcredentials,sec=krb5 --verbose
domain=CERN
mount.cifs kernel mount options: ip=188.184.36.137,unc=\\cerndfs.cern.ch\dfs,sec=krb5,user=CERN\acattabi,domain=CERN,pass=********
mount error(126): Required key not available
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)