Enemy Units are still Question Mark?

As you can see I started to Invade his capital yesterday, at first I thought I can take his capital cause it was only has 17 units while I have 29 unit and 10 Artillery, as I invaded the capital the only thing I saw was only an Infantry with an Question Mark info I can move away my troops or what so ever. So I waited for couple of hours like thinking it was something that happens naturally but after a day it still the same, my units that was supposed to be full Health now is 10 or 15% Health left and I still didn't take the capital.