I launched my attack in war, but connectivity issues (I am assuming it was my WiFi) prevented the attack from starting. I killed WiFi and came back to a lost flag and a zero for the attack.
I attempted to go after the same team again, and noticed that the heroes I had selected for the prior attack were available. I selected them and tried to launch my attack, but an error prevented it from starting. It did not cost me a flag.
I restarted the game and noticed that now the heroes I had selected for the prior attack were unavailable. I selected a different set of heroes and attempted to launch my attack and received an Unknown Target error. It did not cost me a flag.
I am stepping away from the battlefield for a bit.