It's just not a good fit, they are totally out of ideas against a parked bus and Messi is not getting any time on the ball or able to find and pockets of spaceMessi is a huge part of this problem too though.
He's walking around too much without pulling them the other way and its hurting the teams shape.
He's simply not making space for himself or his teammates.
Really not much he can do as he's faced with so many players too close to him to do anything with the ball unless he is able to come up with some sort of magic but it hasn't looked it at all