This error means that for some reason the quest is not available for you. Unfortunately, it happens that such quests are displayed in available for capture, but when you try to take them - error 704 appears and the quest disappears from the list of available for capture, as it should be.
Remember, not all quests should be available to complete it. There are various connections, for example, completing one quest makes the previously available quest inaccessible for you. Or a quest in the future will not be available to you if you complete / did not complete another quest.
