Are you sure about the capital "R" in typing "root" credentials...? So if you are, it does not seem to be normal. However, please check the /var/log/auth.log file for more information about whatever happened on the ESXi local account ...Please mark my comment as the Correct Answer if this solution resolved your problem
I reset the password once again to make sure that I didn't fat finger anything. I rebooted and tried both "Root" and "root" as login. Instead of logging into Putty this time I just tried to log into the GUI.
- Looking into the logs Amin mentions I noticed "pam_access(sshd:auth): access denied for user `root'"
- I found a posting stating to go to /etc/ssh/sshd_config and confirm "PermitRootLogin" was set to yes
- Right clicking on the Host inside the ESXi GUI and selecting Permissions
- I noticed "root" was not listed in this directory
- Adding the root account back here allowed me to SSH back in again.