Golle, Zhong, Boneh, Jakobsson, and Juels recently presented a very efficient mix-net, that they claim to be both robust, and secure. We present four practical attacks for their mix-net, and break both its privacy and robustness. Each attack exploits and illustrates a separate weakness of the protocol. The first attack breaks the privacy of any given sender without corrupting any mix-server. The second attack requires that the first mix-server is corrupted. Both attacks are adaptations of the ``relation attack'' introduced by Pfitzmann. The third attack is similar to the attack of Desmedt and Kurusawa and breaks the privacy of all senders, and robustness. It requires that all senders are honest, and that the last mix-server is corrupted. The fourth attack is novel and breaks the privacy of any given sender. It requires that the first and last mix-servers are corrupted. This attack breaks also ``Flash Mix'' by Jakobsson, including the fixed version given by Mitomo and Kurosawa.