My cisco box time is off by two or 3 minuets

My Cisco box a.k.a. cox cable box is slow by two or 3 minuets. I unplugged it and plugged it back in; that didn't work. It's very frustrating because I miss the first few minuets of my program, plus I use it as a clock when I'm getting ready for work. I looked in the settings and saw nothing about Adjusting the clock. The hour on the clock is correct but the minuets are slow  by a few seconds and I hope To get some help on this problem.