I have an AT&T branded LG G4 H810. At work the cell service is terrible. Therefore I put the phone into airplane mode and rely on WiFi calling for my service. Anytime I make a call or send a message it works flawless. But, I do not receive all my messages, and maybe even miss some calls. I Would say 50%of the messages aren't being delivered. I am able to open the Att.messages.net and see the messages are delivered to AT&T, but they are not being pushed to my phone. The ones that are not delivered, will show up after I have left and turned the 4G back on. Usually they will come all at once. Some of these are delayed as much as 8hours. Sometimes the push will not happen till after I have had good signal for up to an hour. As I mentioned earlier, the messages do appear on the Att.messages.net site immediately. The dropped messages are not related to the sender carrier. Messages originating from Senders straight talk, Verizon and AT&T both have had the same behavior. A co-worker who is also on AT&T has a Galaxy S7. He has also reported the missed calls and messages. For testing purposes I ran my phone in airplane mode with WiFi calling at home and also had messages not delivered. So I have ruled out the WiFi network at work. I have also used the stock messaging app as well as Textra with the same results. My phone is set to keep WiFi active while the phone is locked. Battery saver did not make a difference. It does seem the messages are more likely to come through if the phone is unlocked, but I have still have had failed ones In this state. Has anyone else experienced this? And ideas or suggestions?