It is accepted—and, indeed, I just double checked, and it worked. In fact, I've now switched the best answer to "are sleeping". I suspect you, like many others, made an error with the nouns (i.e. taoba is singular and valī is plural, so it's not "The boys and the men are sleeping", but "The boy and the men are sleeping"). Every single suggested answer I received in the error section was wrong for either this reason, or for inappropriate ordering (i.e. putting "men" first).