Unit is not facing target?

[CountryBoy]

Hopefully someone can let me know why this is happening.

In the image below, I am trying to order the middle grouping of artillery to fire on the French infantry, either the nearest units or the ones further away. The artillery unit is unlimbered and has not moved this turn. When I select the unit and try and fire on any of the French infantry in LOS I get a message "Firing unit is not facing target". The same applies for the artillery unit to the south of the middle unit. Why is that? How can it be that it is not facing the target? Any assistance is appreciated.