I'm also facing the same issue :( I use  iOS system version to 14.6, watch os version to 7.5 In my project, I use WatchConnectivity between phone and watch to communication, When watch send message without reply to phone, every time is OK. But when need reply from phone, it's wrong. func session(_ session: WCSession, didReceiveMessage message: [String : Any], replyHandler: @escaping ([String : Any]) -> Void) { // replyHandler(reply) } when debug the code, I can see this func was called, but watch not receive reply. I try to edit scheme then switch debug to release, run the project. but failed. Is there any ideas?