Can't Login to my Server via SSH, and the password is correct

You need to run ssh (the client, and possibly the server) with more verbosity to understand why authentication is failing. For the client, run

ssh -vvv username@host 

On the server end, check the logs. /var/log/auth.log will give you a pretty good idea about what happens when you try to login, look for messages that contain sshd. There are a variety of reasons why authentication could be failing, ranging from simple (you aren't using the right username) to more complicated (sshd is configured to use the wrong authentication system).