The PDP needs to be removed or changed
Under System Configuration>Distribution Points, identify the gateway that acts as the PDP.
Under System Configuration>Gateways, back up any custom settings, then delete the gateway noted above
Click the key that now shows up next to delete and edit, to the right by the gateways. On the first one, choose that you want it to be the PDP from the pull down menu. Copy the command and run it on this device. The PDP should be a Threat Isolation Engine.
Click the key to the right for the rest of the gateways that will use this PDP. Choose the PDP off the pull down options, then copy the provided command to re-register them.
If needed, add a new gateway for the PDP that was deleted and restore the previous settings.