I have an Aukey CB-C78 Hub to a Dell XPS 15 9550 connected through the Thunderbolt port to a VGA cabled E85LCD Mitsubishi monitor. The computer has found the monitor once, and then stopped detecting it. Bought the CB-C78 because it had the VGA port. The mouse and printer both work through the port as expected. And the other ports seem to work. Only the VGA connection is failing, what do I do?