MacBook Pro mid2015 dual Monitors, HDMI blacking out

I have a MacBook Pro mid2015 with an upgraded hard drive and I have recently attached dual 2560X1440 monitors. One is connected through the mini DVI port and the other through the HDMI. The HDMI cable I am using is a high definition cable but my monitor keeps blacking out whenever I am using the monitor and the display is changing. I saw a post for a similar issue form a few years ago and the resolution that was posted as being acceptable is greater than what I am using. Are there any changes I can make to improve the display or understand what’s happening?