In phpmyadmin make sure sentora_postfix.vacation_notification table exists, if not add it:
Code:
CREATE TABLE `vacation_notification` (
`on_vacation` varchar(255) NOT NULL,
`notified` varchar(255) CHARACTER SET latin1 NOT NULL,
`notified_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`on_vacation`,`notified`),
CONSTRAINT `vacation_notification_pkey` FOREIGN KEY (`on_vacation`) REFERENCES `vacation` (`email`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Postfix Admin - Virtual Vacation Notifications';