Exclamation mark badge on iPhone Messages app icon

Having updated to iOS 11.2.5 yesterday, the exclamation mark that appeared on start-up has gone and tests today suggest that iMessages sent when the phone is switched off are delivered when the phone is switched back on. I would be very interested to hear if others have the same experience. Assuming they do, it looks as if the problem has been solved. Fingers crossed!

At your suggestion I updated to iOS 11.2.5 yesterday and the explanation mark that appeared upon start-up is now gone as you said. Thanks so much for being the champion on this and seeing it through!

I have the same problem on my 6S. It first occurred when I updated to iOS 11.2. The update to 11.2.1 didn't resolve the issue. Having now discussed the issue with Apple Support in the UK on three occasions (including a screen sharing session), I too have gone through the reset, restore route with no success. It appears that Apple Support are aware of the messages not appearing issue but not, it appears, the presence of the exclamation mark upon start-up. I will contact Apple Support after the Christmas holiday period and report back if a solution is found.

As this was the third or fourth time I have contacted Apple Support about this issue, my call was esclated to a senior advisor. After discussing the matter at some length (he was extremely helpful), he undertook to liaise with the engineering team and report back to me in, he hoped, three to five days. Altough unfamiliar with the issue, he speculated that it may be the case that the phone is de-registering from iMessage when it is switched off and re-registering when it is switched back on. I will report back when I know more.

When you say the phone is off, do you mean the phone is just locked, or it's actually powered off completely? If the latter, how would you expect to receive messages if the phone is off? Maybe I'm just not understanding your issue.

If my phone is completely off, I can receive both SMS and iMessages after I power it back on. As in Off. Not sleeping. The same goes for "No Service" if I'm in a black hole or underground.

I don't have this issue.

As promised, an update. My fix was short lived. The exclamation mark has returned and my iPhone is no longer receiving iMessages when switched off (it continues to receive SMS when switched off). I will revert to Apple Support in the first week of the new year and report back.

Have you received a response to the red explanation point in your Message icon when powering phone back on? I just updated to IOS version 11.2.1 and the problem began. I also believe I am now not getting iMessages that are sent when the phone is powered off and then powered back on

I am still waiting to hear from Apple Support. If I dont receive a response by the end of the week, I will contact them again. In the meantime, I updated to iOS 11.2.2 this week and while the exclamation mark remained, for a short time yesterday I received imessages sent to my phone when it was switched off. Sadly, that is no longer the case.

As Apple Support didn’t get back to me as promised, I contacted them again this evening. I was redirected to a senior advisor (based in the US). In short, the problem has still not been fixed. He did, however, take “ownership” of this issue and undertook to keep me advised of progress. I will post again when I have anything new to report.

That is certainly odd. I wish I had a solution for you, but I just don't.

Most of my friends have iPhones, so I don’t know about SMS (I will check in the next day or so and let you know). I can confirm it does receive iMessages when switched off.