Dell XPS-12 duel monitor issues

I have a UD-3900 that has been working fine until now. I’ve been only working using one monitor on the HDMI port. I just purchased two new 27" Asus monitors and I can only get one of them to work on my hub through the VGA/DVI connection. If I put my second one into the HDMI, it says that it will not connect. I know that both monitors work (I plugged the VGA/DVI connector into both). I know that the HDMI will work because it did before I received my new monitors. I know that it isn’t my Dell XPS 12 - because at work I have no issues with two monitors. I’ve also updated my Intel drivers. I’m at a loss as to what to do next. I don’t want to have to return to working with just one monitor.
Any direction would be greatly appreciated.