Im a dumb... i was declaring a foreign key in the wrong table..
CREATE TABLE IF NOT EXISTS `beta`.`msg_messages` (
`id_msg` BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT ,
`id_user_from` BIGINT(20) UNSIGNED NOT NULL ,
`subject` VARCHAR(200) NOT NULL ,
`body` TEXT NOT NULL ,
`date` DATETIME NOT NULL ,
PRIMARY KEY (`id_msg`) ,
INDEX fk_msg_messages_user (`id_user_from` ASC) ,
CONSTRAINT `fk_msg_messages_user`
FOREIGN KEY (`id_user_from` )
REFERENCES `beta`.`user` (`id` )
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
CREATE TABLE IF NOT EXISTS `beta`.`msg_messages_users` (
`id_msg` BIGINT(20) UNSIGNED NOT NULL ,
`id_usr_to` BIGINT(20) UNSIGNED NOT NULL ,
`status` TINYINT NOT NULL DEFAULT 0 ,
`date` DATETIME NOT NULL ,
INDEX id_msg (`id_msg` ASC) ,
INDEX fk_msg_messages_users_msg_messages (`id_msg` ASC) ,
INDEX fk_msg_messages_users_user (`id_usr_to` ASC) ,
CONSTRAINT `fk_msg_messages_users_msg_messages`
FOREIGN KEY (`id_msg` )
REFERENCES `beta`.`msg_messages` (`id_msg` )
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT `fk_msg_messages_users_user`
FOREIGN KEY (`id_usr_to` )
REFERENCES `beta`.`user` (`id` )
ON DELETE CASCADE
ON UPDATE CASCADE)
ENGINE = InnoDB;
thanks all