In this paper, one of the most important challenges in energy smart grids – Denial of service for critical time messages – is addressed. In order to explain and solve this issue, we have described different communication structures for conveyed messages in energy smart grids, various proposed communication technologies, different types of jammings, and variety of conveyed messages in grid. Also, depending on communication technology and jamming in use, different situations of jamming is explored. To describe jamming problem, Gambler’s ruin problem solving theory is used. To eliminate this vulnerability, the least rate of invalid messages is calculated for the worst situation. TACT technic in he least camouflage traffic load in grids is used to match this problem to real world.