When iMessage won’t send on my iPhone, iOS gives me one of two warnings: a red “Not Delivered” alert under the bubble, or the bubble flipping green because my phone quietly fell back to standard SMS. After years of fixing this for family members, I have learned that both signs point to the same thing. Something is blocking iMessage from reaching Apple’s servers, and the cause is almost always small.
The triggers range from a lapsed Apple ID session to a weak Wi-Fi signal, and most take under two minutes to clear. I work through the steps below in order, because the first one resolves it for me roughly nine times out of ten.
Quick Answer
Open Settings, tap Messages, and toggle iMessage off. Wait 10 seconds, then switch it back on and give it up to a minute to re-register. If the bubble is still green, confirm you are signed into your Apple ID and that your internet connection works. Most iMessage failures clear in under a minute this way.
The single most reliable fix is toggling iMessage off and on to force a fresh session.
Why does iMessage turn green or say “Not Delivered”?
A blue bubble means your message travelled over Apple’s iMessage network, end-to-end encrypted and free over Wi-Fi or cellular data. A green bubble means iOS fell back to SMS or MMS through your carrier, which may cost money and drops read receipts. A “Not Delivered” notice means the message failed entirely and reached the recipient by neither route.
What each warning sign means
The first time I saw a green bubble to my sister, I assumed iMessage was broken on my end. It was not. The colour and the error each map to a specific cause, so reading the sign correctly saves you from chasing the wrong fix.
| Cause | What you’ll see |
|---|---|
| iMessage disabled or signed out | All bubbles turn green |
| No or weak internet connection | “Not Delivered” or stuck “Sending…” |
| Recipient’s iMessage is off | Green bubble (their end, not yours) |
| Apple server outage | Multiple recipients affected at once |
| Device clock set incorrectly | iMessage fails to authenticate |
Match the sign to the table first, then jump straight to the fix that fits.
How do I toggle iMessage off and back on?
This clears a stale session token, and it is the first thing I try every single time because it works so often.
- Open Settings and tap Messages.
- Toggle iMessage off.
- Wait 10 seconds.
- Toggle iMessage back on and wait up to 60 seconds for registration to complete.
If you also use FaceTime, toggle it off and on at the same time, since it shares the same Apple ID authentication layer. When FaceTime is misbehaving too, my guide on fixing FaceTime when it won’t connect walks the same sign-in path.
Toggling iMessage forces a fresh registration with Apple and fixes most failures on its own.
What if my internet connection is the problem?
iMessage needs an active internet connection, and when my signal is weak the messages either queue up or fail silently with no obvious reason.
- Open Safari and load any website. If it fails, the problem is your connection, not iMessage.
- On Wi-Fi, go to Settings → Wi-Fi, toggle it off and back on, or move closer to your router.
- On cellular, switch Airplane Mode on for 15 seconds, then off.
Open Settings → Cellular, scroll down, and confirm iMessage is allowed to use cellular data. If that toggle is off, iMessage breaks the moment you leave Wi-Fi range. If pages won’t load at all, my walkthrough on Safari not loading on iPhone covers the connection-side steps.
Confirm a working data connection before blaming iMessage itself.
Should I sign out of my Apple ID and back in?
Yes, when the toggle looks fine but messages still fail, a corrupted iCloud credential is usually the culprit. Signing out and back in rebuilds it.
- Go to Settings → [your name].
- Scroll to the bottom, tap Sign Out, enter your Apple ID password, and choose to keep a local copy of your data.
- Return to Settings and sign back in with your Apple ID.
- Go to Settings → Messages and re-enable iMessage.
A fresh sign-in clears a broken credential that toggling alone cannot reach.
Why does my iPhone clock break iMessage?
iMessage uses your device clock to authenticate with Apple’s servers, so even a few minutes of drift can break the handshake. I once hit this after a long flight across time zones.
- Open Settings → General → Date & Time.
- Enable Set Automatically.
- If it was already on, toggle it off, wait five seconds, then turn it back on to force a fresh sync.
An accurate, auto-set clock keeps iMessage authentication from silently failing.
How do I reset network settings safely?
A network reset wipes saved Wi-Fi passwords, VPN profiles, and cellular APN settings to give iMessage a clean slate. It does not delete your photos, apps, or personal data, which is why I keep it as a later step rather than a scary last resort.
- Go to Settings → General → Transfer or Reset iPhone.
- Tap Reset → Reset Network Settings.
- Enter your passcode and confirm. Your iPhone will restart.
- Reconnect to your Wi-Fi network, then open Settings → Messages and confirm iMessage is still enabled.
Before you reset, check Apple’s System Status page to rule out a server-side outage. A red dot next to iMessage means the problem is Apple’s, not yours.
Reset the network last, and only after confirming Apple’s own servers are healthy.
Common Mistakes to Avoid
- Messaging an email the recipient never linked to iMessage. Fix: switch to their phone number, which is far more likely to be registered.
- Assuming a green bubble means you are being ignored. Fix: accept it usually means the recipient is on Android or has iMessage off, and the message still delivers as SMS.
- Skipping the internet check. Fix: load a website first, because a silently dropped Wi-Fi session causes more “iMessage broken” reports than anything else.
- Force-quitting the Messages app. Fix: toggle iMessage in Settings instead, since force-quitting can interrupt an in-progress sync.
- Ignoring a full storage warning. Fix: free up space, because a packed iPhone can stop the Messages database from writing. My guide on freeing up iPhone storage fast shows the quickest wins.
Frequently Asked Questions
Why does iMessage say “Delivered” but they never got it?
“Delivered” means the message reached Apple’s servers and was pushed to their device, not that they opened it. For example, when my brother’s phone was powered off overnight, my texts showed “Delivered” yet sat unread until he turned it back on the next morning.
Can iMessage work without Wi-Fi?
Yes, iMessage runs over any active internet connection, including 4G and 5G cellular data. I send blue bubbles on the train every day with no Wi-Fi in sight, as long as iMessage is toggled on under Settings → Cellular.
Why do some contacts always show green bubbles?
Those bubbles are green because the recipient is on Android or has iMessage disabled on their Apple device. My one friend with a Pixel always lands as a green SMS thread, and nothing I change on my iPhone will ever turn it blue.
Does resetting network settings delete photos or apps?
No, a network reset only clears Wi-Fi passwords, VPN configurations, and cellular settings. When I reset my own iPhone last month, every photo, app, and message stayed exactly where it was.
Why does iMessage work on my iPad but not my iPhone?
Both devices must be signed into the same Apple ID with iMessage enabled separately. When mine drifted out of sync, I opened Settings → Messages → Send & Receive on the iPhone and found the wrong Apple ID listed there.
What if none of these fixes work?
Contact Apple Support or book a Genius Bar appointment, since the cause may be deeper. A persistent failure I troubleshot once traced to a carrier provisioning issue that only my mobile network could clear from their end.
Conclusion
Most iMessage failures come down to a stale session, a dropped connection, or a clock that slipped out of sync, and all three are fixable in under two minutes. Start with the toggle, work down the list, and you should be back to blue bubbles fast. If wireless sharing is also acting up, my guide on fixing AirDrop when it won’t find devices covers the same network layer.