Bottas had problems with his pit stop and had to retire. And that is it.
Bottas' problem was really hilarious, man.

And it was so unlucky at the same time. They couldn't unmount the right front tire and he had no other thing to do than retiring. And I've heard that the team couldn't even unmount it still after the race. They decided to do it in the factory.
If Bottas didn't have such problem, I think he would have finished at the 2nd place.