Mac Mini blue screen upon wake

Hi! I have a Mac Mini (2014). I recently bought a new Dell monitor to go with the machine. It is connected by a DVI to HDMI cable directly to the Mac Mini. From time to time, when the monitor (it could be the computer that went to sleep as well) wakes, all I get is a blank screen. I know the computer is awake because attempts to use the keyboard give me a bump sound. However, the monitor is unusable. I can correct the problem by rebooting the computer. I am not sure if this is a cable handshake issue or some sort of HDCP complication gone awry. Any help would be great. Thanks.