Access denied using Putty

[rocket123]

I used to be able to login using Putty.

Now, I get an "Access denied" error after entering password.

Steps:
1. enter ip and click open
2. enter "root" in popup screen
3. enter root password and get this:
Using username "root".
root@12.123.123.123's password:
Access denied
root@12.123.123.123's password:

I'm not a "server" person, but understand it. I tried to use the keys method, but cannot login to even complete the steps.

Any help would be appreciated.