This is not a bug within VMware Cloud Director.
This issue occurs when attempting to use an incorrect key password during the import process for a certificate.
/opt/vmware/vcloud-director/etc/cell-management-tool certificates -j -p --cert /PATH/cert.pem --key /PATH/cert.key --key-password key_password
The value specified for key_password needs to be retained and saved somewhere secure as it is not recoverable.
Should you not know the value of key_password, you will need to either recreate the the certificates, or contact the person responsible for doing so.
For information on how to create a new Self-Signed or CA-Signed certificate in Cloud Director, please see the Create and Import CA-Signed SSL Certificates in VMware Cloud Director
"Error executing command: No valid private key password provided"
This error also can be present if the existing certificates are corrupted and the existing certificates' password cannot be matched against the one in the command
If possible and available you can replace the existing certificates files with the correct ones and then proceed with the replacement (the location of these files will be visible inside the global.properties file)
if not possible certificates need to be recreated from scratch using the steps from 'Resolution'