ESXi root account password operations in SDDC manager fail with: "Validation of password of ESXi host: <ESXI FQDN> has failed. Check if the password used to connect to ESXi host is valid."
You will also see: "Cause: {vim.fault.PasswordExpired}"
VCF 5.x
ESXi host password had previously expired, causing future password remediation tasks to fail.
Simply changing the password doesn't address the issue. You must set the ESXi password to what is stored in 'lookup_passwords' on the SDDC manager.
See: Look Up Account Credentials
You can set the ESXi root password expiration temporarily to '9999' to allow for the remediation to complete.
See: Configure the Local User Password Expiration Policy for ESXi