Suppose, the server address is abcd.com. On my local machine at my workplace, I have to login to that server, using
ssh <my employeeid>@abcd.com
Then, to login to user myname , I have to use
su - myname
This way I login, but why can't I directly login to that server using
ssh myname@abcd.com
/var/log/auth.log. The user is probably not allowed to use SSH. Other ways to find more information is to make ssh more verbose with one or more -v flags or to run the daemon with a -d (debug) flag. – jippie Apr 15 '12 at 12:42