For the initial broadside, it's common for a ship to fire with it, then not be able to until it can move closer, have a rake, etc. Check your ships in the events on the left-hand part of the page -- it will show what HDT it calculated for each one. If it's -1 or below, that ship can't fire until it has zero or above.

If you loaded something other than "round" shot (grape, chain, or double), you might be out of range for them.

If you're still not sure, post the game number or link and we'll look at it.

Happy hunting!