Check the network, tap the red alert and retry, then use Send as Text Message when appropriate. Confirm the correct number under Settings > Apps > Messages > Send & Receive, restart iPhone, and contact the carrier for SMS, MMS, or RCS failures.
If iMessage is unavailable and the message can be sent as SMS, tap the alert and choose Send as Text Message. Carrier charges may apply.
3
Confirm Send & Receive
Open Settings, choose Apps, then Messages and Send & Receive. Make sure the correct phone number and Apple Account addresses are selected.
4
Restart and update
Restart the iPhone, install an available iOS update, and check with the carrier for a settings update or SMS-service issue.
5
Contact the right provider
Contact Apple for iMessage problems or the carrier for SMS and MMS problems that continue.
6
Retest the original symptom
A new message and an attachment reach the intended recipient and a reply returns after the supported account, carrier, or network check.
7
Troubleshoot iPhone message sending
If only one contact fails, activation remains pending, the carrier rejects SMS, or the Apple Account shows an unexpected address, stop broad resets and return to the last known state. Capture the exact error, versions, device or account scope, and failed step before using the linked official support channel.
Video walkthrough
ⓘ Sources and verification
Checked against official documentation on . Scope: iPhone.
Follow the linked first-party guidance if labels differ after a platform or app update.
