HP Ultra Slim Docking station not working with Display port when plugging in two monitors

[bctech]

I need help with Ultra Slim Docking Stations. The techs and i are getting calls that the display has gone out on one of their monitors. We go to call to find out that the ultra slim docking station is not taking both monitors. We unplug the one that is connected to VGA and it works with display port.  The vga works everytime but the display port does not work with two external monitors plugged in.  We have tried updates, including firmware. No fix. The only thing that worked for a little while is that we find an old ultra slim that has not been plugged in to a network port or a laptop. We will plug that in and it works fine for a couple of months then it will do the samething. Cant do two monitors. i've seen alot of forums and tried them. nothing works. Anyone have any suggestions. Maybe another update that i cannot find. Anything will help. Thanks 

[banhien]

@bctech 

What is your machine ? Which generation of the HP Ultra Slim Docking station do you have. The current generation is compatible with the following machines:

HP EliteBook Folio 1020 G1
HP EliteBook Folio 1040 G1, G3
HP EliteBook 1040 G2
HP EliteBook Revolve 810 G1, G3
HP EliteBook 800 G7
HP EliteBook 820 G1, G2, G3, G4
HP EliteBook 840 & 850 G1, G2, G3, G4, G5, G6
HP EliteBook 830 G5, G6
HP EliteBook 720, 740, 750 G1, G2
HP EliteBook 725 G3, G4, G5
HP EliteBook 745, 755 G3, G4, G5, G6
HP EliteBook 735 G5, G6
HP ProBook 640, 650 G2, G3, G4, G5
HP ProBook 645 G2, G3, G4, G5
HP ProBook 655 G2, G3, G4
HP EliteBook Folio 9480m, 9470m
HP ZBook 14u G4, G5, G6
HP ZBook 15u G3, G4, G5, G6

Regards.

[bctech]

We have HP ProBook 650 G5.