MoCA adapter doesn't work

I purchased 2 Motorola Moca adapters to get wired connection for computers in my upstairs room. At first I wanted to see if I could get it to work with only one adapter since the panoramic modem already has moca. When that didn't work I brought out the second adapter plugged it into the modem, It worked momentarily but then the modem light started blinking and completely lost connection to the internet.