SSH not working for particular user

[Francisco Reyes]

Besides the AllowUsers parameter in sshd_config is there is anything else 
that would allow certain users, but not others to ssh to a machine?

Have a machine that one id can connect to, but not a second one..
I "inherited" the setup (about 20 machines) so don't know yet what setups 
each machine has yet. Have an ID I was given to login, but now going to 
each machine to create my own ID.