CentOS7 extend display, two monitors

I am new to CentOS7 and I am trying to extend my display. I have an Intel graphics chip. I connected the second display to the same graphics card and it is currently only mirroring the first display. I can find no evidence that the system even recognized it as a second screen. What do I have to do to use the second screen as extension?

Desktop environment: GNOME and XFCE
Kernel: 3.10.0-327.36.3.el7.x86_64
One screen is connected to a DisplayPort and one to DVI.
VGA compatible controller: Intel Corporation Sky Lake Integrated Graphics (rev 06)

When running

xrandr -q

I get this:

xrandr: Failed to get size of gamma for output defaultScreen 0: minimum 640 x 480, current 1680 x 1050, maximum 1680 x 1050default connected primary 1680x1050+0+0 0mm x 0mm   1680x1050      0.00*   1280x1024      0.00   1024x768       0.00   800x600        0.00   640x480        0.00