iPhone tower · floor

How to enable iMessage, and the three things it needs

The switch is in Settings → Apps → Messages, and turning it on takes a second. Everything interesting about this question is what has to be true before that second works — and one of the conditions costs money.

With that established, the switch itself. Apple puts iMessage under Settings → Apps → Messages, which is worth saying because the Apps section is newer than the habit of looking for Messages directly in the settings list.

If the switch goes on and stays on, there is nothing more to do. If it does not, Apple names three conditions and an error message for each failure — “An error occurred during activation”, “Could not sign in, please check your network connection”, and “Unable to contact the iMessage server. Try again.”

The time zone is the one worth dwelling on, because nothing about the symptom points at it. A phone with the wrong time zone is a phone whose idea of “now” disagrees with Apple’s, and Apple lists that among the three things to check before anything else. It costs ten seconds to verify and is the kind of setting that goes wrong quietly — after travel, after a restore, after a change that had nothing to do with messages.

That charge, where it applies, is worth understanding rather than resenting. Your phone number has to be proved to be yours, and the way a phone proves it is by sending a message from it. There is no cheaper mechanism available to a phone that has not yet activated the free one.

One detail in that sequence is easy to skip and is the reason it sometimes seems not to work: it covers FaceTime too. Apple has you turn off Messages, then go back out to Settings, then turn off FaceTime, and only then turn both on again. The two share an activation, so resetting one without the other is resetting half of it.

Apple also gives two routes that do not involve the phone at all. The first is activating online through your Apple Account — under Enable Apple Account, tap Get Started, sign in and follow the instructions, entering the phone number if you use one with Messages and FaceTime. Apple adds what to expect: “You will receive an email if your account is ready.”

The second is to sidestep the phone number entirely and use an email address with iMessage and FaceTime instead. Apple’s instruction is to review the addresses on the Apple Account, correct any that are wrong, and click Resend beside the one to verify. For anybody whose activation is stuck on the number — a new SIM, a changed carrier, a number that moved — that is the documented way round it.

The red exclamation mark. A separate Apple page covers the message that will not go: “If you try to send a message and you see a red exclamation point with an alert that says Not Delivered” — check the network, tap the exclamation point, then tap Try Again. And if it still will not go: tap it again and choose Send as Text Message, with Apple’s note attached — “Messaging rates may apply.” That is the same trade as the green bubble, taken deliberately: the message leaves by the carrier’s route instead of Apple’s, and the carrier’s route is the one you pay for.

There is one more situation Apple documents separately, and it explains a specific disappointment: messages that turn green after setting up a new device, or conversations that split into separate threads. Apple’s remedy is a checklist rather than a fix: update iOS, then Settings → Cellular and make sure the phone line is turned on — “If you use multiple SIMs, make sure that the phone number you want to use is selected and turned on” — then turn iMessage off and on, then tap the phone number you want to use with Messages.

That last step is the one that is easy to walk past. Having iMessage on is not the same as having chosen which number it uses, and on a phone with two lines the difference decides which of your numbers your messages appear to come from.

What this page will not tell you is how long activation should take, or what to do if it never completes. Apple maintains separate articles for a stuck activation and for a number that will not verify, and those are the places to go — a page that improvised a waiting time would be inventing the one number readers most want.

The floors below take it three ways: the switch and its conditions, the bubbles and what they mean, and the neighbouring settings in Messages.

What this tower will not do

It will not tell you a green bubble means something is broken. Apple defines it as a message sent by RCS, SMS or MMS rather than by iMessage, which is a route and not a fault.

It will not skip the charge. Apple says activation needs an SMS and that a carrier might bill for it, and a page that left that out would be hiding the one cost involved.

And it will not guess how long activation takes. Apple keeps separate articles for a stuck activation, and inventing a waiting time would be inventing the number readers most want. What holds instead is simple: the definitions of blue and green bubbles, the three prerequisites of a network, current iOS and a correct time zone, the activation error messages, the statement that SMS is needed to activate a phone number and that a carrier might charge for it, the prompt wording and the instruction to tap Turn On, the sequence for turning iMessage and FaceTime off and on again, the online activation route through the Apple Account, the alternative of using an email address, the Not Delivered and Send as Text Message steps, and the checklist for messages turning green on a new device are quoted from Apple’s support documentation, listed below.