OpenSSH 7.8 Client Not Supported
Users running OpenSSH 7.8 can experience authentication failures with PrivX.
Due to a known issue in OpenSSH 7.8 related to how it handles certificate-based authentication, OpenSSH 7.8 client is not supported by PrivX.
Potential Solution
Upgrade your OpenSSH client to version 7.9 or later, where the certificate-based public key authentication issue has been fixed.
Consult your OS vendor's documentation for instructions on upgrading the OpenSSH client.