This is a text message in Zen's route, Day 9. Should I not really receive any reply from him or is this some kind of bug? The same thing happened in Jumin's
Mystic Messenger Yoosung route chat schedule – Day 5, 6, 7, 8, 9, 10 and 11 (Casual mode) | VG247
Mystic Messenger - ZEN's Route Day 5 to Day 10 (GOOD END) - Jin's Records
Mystic Messenger - ZEN's Route Day 5 to Day 10 (GOOD END) - Jin's Records