Every time we do a Remote Control Workstation, a "Verify Managed Device
Certificate" dialog box pops up. It says:

Unable to verify the identity of <device name.domain.com> as a managed
device. The certificate as been self signed by the device and canot be
verified using the trusted certificate. Before accepting this
certificate, examine the certificate carefully. You may verify if using
the fingerprint displayed in the Remote Management section in the
Z-icon on the device.

There are three options: Accept this certificate permanently, Accept
this certificate temporarily for this session, and Do not accept this
certificate and terminate connection.

There are also three buttons: Certificate Details, OK, and Cancel.

Why does this dialog box pop up each time and is there anything we can
do to stop it?