Herobox Pro - Can't get 1080P on VGA (dual monitors)

I bought the Herobox pro to use as a dual monitor workstation. I have two Samsung monitors that work with 1080P over HDMI. When I try to use one on HDMI and one on VGA, the VGA one will only go up to 1024x768. I’ve installed the monitor drivers, and even tried to create a custom resolution in the Intel graphics control panel (which errors out for some reason).

Is 1080P over VGA not supported? Or does anyone have any suggestions to make it work properly?