http://sn.1w6.org/file/lnxw48-20150516T171419-h7yj6m7.html
@mk @kat @mmn I know this is already solved, but putting this here for future reference: On the client side, permissions have to be correct on ~/.ssh/ ... that directory and its contents should not be acccessible for any other users. This may not have been the problem in this case, but I have run into it in the past.