Classical Electrodynamics is Flawed

TWO CANCELING PHOTONS IN A BOX
WHERE DOES THE ENERGY GO?

Consider two photons in a box -- with the two photons 180 degrees out of phase.  The photons each carry one unit of energy, but because they are 180 degrees out of phase, the electromagnetic energy density is zero, as is the Poynting vector.  Therefore, if we follow conventional reasoning, we have lost two units of energy and thus have a violation of energy conservation.  But that is not allowed.  We must thus deduce that classical electrodynamics has a flaw within it. That flaw is addressed when we include scalar electromagnetic energy -- as it has come to be called.