ESXi 6 - How to Unlock Your SSH Account.

ESXi Account lockout info:
1.  Accounts are locked after 10 failed attempts through SSH and the vSphere Web Services SDK.
2. The Direct Console Interface (DCUI) and ESXi shell do not support the account lockout feature.
3. The account automatically unlocks after 120 seconds by default.
4. ESXi leverages the Linux Pluggable Authentication Modules (PAM)

If you are unable to wait for the account to unlock, you can reset the account by doing the following:
1. Console into your server by using your DRAC/iLO/UCS Manager etc.
2. log in as root, and run the following command to unlock the account.  In the example below, you can see there was 11 failed attempts:

pam_tally2 --user root --reset