There was problem with somes keys,
look at your host messages (/var/log/auth i guess)
if you get a message like
48:de:55:22:xx:yy:zz:yy:xx:yy:zz:yy::88:e8:87:47 blacklisted (see ssh-vulnkey(1))
that's you need to re-create your key on client and re-send on host.

Kytrix