a stack of units is unresponsive

Hello. I have a stack of units attacking into an enemy province,

however, it has become totally locked up. It will not let me move it, it

says its attack power is zero despite having at least six light tanks,

and it will not let me exit the menu of the unit stack once i click on

it. ive tried reloading the game and playing on a different device to no

avail. can someone tell me whats going on, and if i can get my troops

back?

-Picture of stack-