Will iMessage be re-delivered when the recipient attains wifi access? I went into Settings > Messages > Learn More and it says that iMessage only works in Wifi mode. I am on Wifi and I have been trying to send iMessages to another person. Each time I send it "delivered" appears under the message. The other person calls me saying that she has not been receiving my iMessages. However, when I turn off iMessage in Settings > Messages, she starts responding to me, implying that regular SMS messages work. I am wondering whether the iMessages that I've sent have disappeared forever or will she start downloading the undelivered iMessages them when she attains wifi access?
My guess is that you both need to be on wifi, or you need to restart BOTH of your devices.