Recently, I needed to add a user to our CentOS server. For some reason, I could not add or remove them using useradd or userdel, so I edited /etc/passwd and /etc/shadow manually, adding them. I was then able to use passwd as root to change their password, and all was well.
Or so I thought. Now, some users aren't able to log in via SSh at all - when prompted for their password, they're given
Permission denied, please try again. for three attempts, then
Permission denied (publickey,gssapi-with-mic,password).
This may be unrelated to the changes to /etc/passwd and /etc/shadow - removing the changes to those files doesn't solve the problem.
EDIT 1: The new user is able to log in via ssh, but some older users (including root) are not. The problem is also ONLY with ssh - logging in on the physical machine, and using su, both work without problem.