glitch in "Arctic Explosion" adventure?

I can't get any of my generals to attack the northwest (medium) camp. Finished all the other camps and the leader but stuck on this one. It was the first camp I tried to attack and I've tried different generals but same results. I've gone back to the home island and returned but nothing helps. Any suggestions?
Thanks!

I have been told that you have to move your general as it blocks the attack path.

Thanks! I moved everyone out of the area and it worked fine.