My ships just vanished.

Enemy attacked my 2 ships with a stack of 12 ships, I separated the two ship (a battleship and a cruiser), restored the battleship's health to full then pulled away from the fight, and sent the cruiser to take all the hits. A "error" message popped up then my battleship vanished after successfully pulling away, after about 3 seconds the cruiser vanished too.

Please help!