Beaglebone ssh

I have my beaglebone connected to my router and I am trying to ssh to it through ubuntu. I found the right ip that was assigned by dhcp to it, but when i try to connect, it is asking for (publickey, password). I have previously connected to the bone through minicom, so i did set up a root and password, and I’ve tried that and other passwords but none work. Can anyone help me to solve this problem? Thanks, Carter