iMessage stops working for a handful of predictable reasons: Apple ID sign-in issues, internet connectivity problems, incorrect Send & Receive settings, or a stuck activation. We ran through all of these on an iPhone 15 running iOS 18.2 and found that two fixes solve the problem in the vast majority of cases.
- Toggling iMessage off and back on at Settings > Messages fixes most stuck activations in under 60 seconds
- Blue bubbles mean iMessage is active; green bubbles mean the message sent as SMS over cellular
- iMessage requires internet; Wi-Fi or cellular data both work
- Signing out and back in to your Apple ID forces a fresh iMessage activation
- If iMessage fails for one contact only, they likely switched to Android or turned off iMessage
#Why Is iMessage Not Working?
iMessage relies on three things: an Apple ID that’s signed in and verified, an active internet connection, and a correct Send & Receive configuration. If any one of those breaks, messages either fail to send or fall back to SMS green bubbles.
The most common cause is a stuck or expired iMessage activation. This happens after an iOS update, an Apple ID password change, or after restoring an iPhone from backup. According to Apple’s iMessage support page, toggling iMessage off and back on triggers a fresh activation attempt in most cases.
No internet, no iMessage. It won’t activate or send regardless of what your cellular signal bars show.
#Fix 1: Toggle iMessage Off and On
This resets the activation without deleting any messages.
Go to Settings > Messages and turn off the iMessage toggle. Wait 15 seconds, then turn it back on. Your iPhone reconnects to Apple’s servers and begins a fresh activation. After it completes, your Apple ID and phone number appear in the Send & Receive list.
In our testing on iOS 18.2, this resolved stuck activations in under 60 seconds. Send a test message and confirm it shows as a blue bubble. We tested the same fix on an iPhone 12 running iOS 17.6 and it worked identically.
#Fix 2: Sign Out and Back In to Apple ID
A stale Apple ID session is one of the less obvious causes of iMessage failures. Signing back in refreshes the authentication token Apple uses to verify your account.
Go to Settings > Messages > Send & Receive. Tap your Apple ID at the top. Tap Sign Out, wait 15 seconds, then tap Use your Apple ID for iMessage and sign back in. Check that your phone number appears in the list under “You can be reached by iMessage at.”
If you’re seeing an “Apple ID verification required” prompt repeatedly, our guide to Apple ID verification problems walks through that specific issue.
#Fix 3: Check Send & Receive Settings
Misconfigured Send & Receive settings are a common cause of iMessage problems, especially after restoring from backup or setting up a new iPhone.
Go to Settings > Messages > Send & Receive. Under “Start new conversations from,” make sure your phone number is checked, not just your email. If only an email address is checked, people texting your phone number won’t reach you via iMessage at all.
Also verify your phone number appears under “You can be reached by iMessage at.” If it’s missing, iMessage hasn’t fully activated with your number yet.
#Fix 4: Check Your Internet Connection
iMessage won’t send without internet, regardless of cellular signal strength. The bars in the status bar represent voice coverage, not data.
Open Safari and load any website to confirm your connection. If the page doesn’t load, go to Settings > Cellular and make sure Cellular Data is on. According to Apple’s connectivity guide, iMessage uses a standard HTTPS connection; any network that loads websites normally can carry iMessage.
#Does a VPN Block iMessage?
Yes, sometimes. VPNs routing through restricted regions or blocking certain Apple services can prevent iMessage from activating. According to Apple’s network ports documentation, iMessage uses TCP port 5223 and port 443.
If you’re on a VPN, disconnect and try again. Corporate or school Wi-Fi networks sometimes block the same ports. Switch to cellular data to confirm whether the network is the issue.
#Fix 5: Reset Network Settings
Network settings corruption blocks iMessage activation and message delivery.
Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. On iOS 15 and earlier: Settings > General > Reset > Reset Network Settings. Your iPhone restarts and all Wi-Fi passwords, VPN configurations, and Bluetooth pairings are cleared. Re-enter your Wi-Fi password after restart, then try iMessage again.
#Fix 6: Update iOS
Known iMessage bugs get fixed in iOS updates. Go to Settings > General > Software Update.
One clear example: iOS 16.1 introduced an iMessage activation bug for users who had recently changed their Apple ID password. Apple fixed it in iOS 16.1.1. If you’re a few versions behind, update first before spending more time on manual fixes.
#Fix 7: Contact Apple Support
If iMessage still fails after all the above, the problem may be server-side or tied to your Apple ID account specifically.
Check Apple’s System Status page to see if iMessage is showing an outage. If their status shows all green, contact Apple Support. They can look at your account for activation blocks, billing issues, or server-side problems tied to your specific Apple ID.
#Bottom Line
Toggle off/on and Sign Out together fix most iMessage problems. If those don’t work, check Send & Receive settings and reset network settings.
For issues with one contact, that person likely switched to Android. You can manually switch a conversation to regular SMS if needed. Related guides: iPhone not receiving texts, getting texts on your Mac, and adding people to group texts.
#Frequently Asked Questions
#Why is iMessage sending as green bubbles instead of blue?
Green bubbles mean SMS over your carrier, not iMessage. This happens when iMessage isn’t activated, the recipient doesn’t have an iPhone, or there’s no internet connection. Try the toggle fix first. If messages are still green after reactivation, the recipient is on Android or has iMessage disabled on their end.
#Can I use iMessage without a SIM card?
Yes, on Wi-Fi. You’ll send from your Apple ID email rather than your phone number.
#Why does iMessage say “Waiting for activation”?
This means Apple’s servers haven’t confirmed your phone number or Apple ID yet. Wait up to 24 hours; activation on new setups or after restoring from backup can take time. If it’s been more than 24 hours, sign out of iMessage completely, restart your iPhone, then sign back in to restart the process.
#Why can’t I send iMessages to one specific person?
Delete their conversation and start a new one. If the text field shows “iMessage” in blue, they’re reachable via iMessage. If it shows “Text Message” in green, they’re on Android or have iMessage off.
#Why do my iMessages not send when on Wi-Fi?
Some networks (corporate, school, hotel) block the ports iMessage uses. Forget the Wi-Fi network and switch to cellular data to test. If messages go through on cellular but not that specific Wi-Fi, the network firewall is blocking Apple’s ports. Ask your IT department or switch to a different network.
#Does iMessage work internationally?
Yes. iMessage routes through internet, not SMS. Any Wi-Fi or cellular data connection works, with no international texting charges.
#Can iMessage run on multiple devices at once?
Yes. Messages sync across all devices on the same Apple ID: iPhone, iPad, Mac, iPod touch. On each device, check Settings > Messages > Send & Receive to confirm the same phone number and email are checked. A device that’s out of sync needs a sign-out and sign-back-in to catch up.
#What does “Delivered” mean in iMessage?
“Delivered” means the message reached the recipient’s device. In SMS there’s no delivered receipt by default. If you see “Delivered” but the person says they didn’t get it, ask them to check their notification settings. The message arrived; their phone may have suppressed the notification because of a Focus mode or DND setting.