Help my general .....

By the last fight my general and the whole army was defeated.

after a lot of hours the general was back again, now after a 3 days period and a whole new army, I want him to go on war again, but when I do, it says cancel action and stays black, what to do, please help

Have you assigned any troops to the general?

You probably don't have any troops assigned to the general, or want to attack an invalid target.