ESXI-06-000006 - The system must enforce the unlock timeout of 15 minutes after a user account is locked out.
By limiting the number of failed login attempts, the risk of unauthorized access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
From the vSphere Client select the ESXi Host and go to Configuration >> Advanced Settings. Select the Security.AccountUnlockTime value and configure it to 900. or From a PowerCLI command prompt while connected to the ESXi host run the following commands: Get-VMHost | Get-AdvancedSetting -Name Security.AccountUnlockTime | Set-AdvancedSetting -Value 900