You can call, browse the web, and even send iMessages on your iPhone, but every green-bubble text message fails to send. When calls and data work but SMS does not, the culprit is often the SMS center number (SMSC) — the address of your carrier’s server that relays your text messages. Normally the carrier writes this number to your SIM automatically, so you never need to touch it. But after a SIM swap, an eSIM transfer, or a botched carrier update, the stored number can go wrong or missing — and iOS shows no visible setting for it. The fix is hiding in a secret dialer-code menu that takes less than a minute.
How to change the SMS center number on iPhone
- Check the current number. Open the Phone app, dial *#5005*7672# and tap the call button. Your iPhone will display the currently stored SMS center number. Compare it with the official number published on your carrier’s support page — a mismatch explains why your texts are failing.
- Enter the correct number. Dial **5005*7672*<carrier number># in international format — for example, **5005*7672*+79043490000# — and tap call. Use exactly the number your carrier publishes on its official support page, and never invent one. As 9to5Mac notes in its coverage of iPhone dialer codes, these hidden codes execute immediately with no confirmation screen.
- Reset to the SIM default. To undo a manual entry, dial ##5005*7672# and tap call. The iPhone clears your change and returns to whatever number the carrier originally stored on the SIM.
- Restart and send a test text. Restart your iPhone, then send a test SMS to yourself or a friend. If it goes through, you are done.
Important: a wrong SMSC number breaks all outgoing text messages, so only ever use the official number from your carrier’s support page.
If the SIM itself is the problem — a new SIM that will not activate, or messages still failing after the number change — see our guide to verifying your SIM card and avoiding the cooling-off period. Dual-SIM users juggling work and personal lines may also like allowing calls from only one SIM in Focus mode.
If it still doesn’t work
Update your carrier settings: go to Settings > General > About and wait a few seconds — if a carrier update is available, you will get a prompt to install it. Also try toggling Send as SMS off and back on in Settings > Messages. Apple Support’s SMS troubleshooting guidance covers these steps in detail. If nothing helps, contact your carrier directly: they can re-provision the SMS center number on your SIM remotely.
Frequently asked questions
Will changing the SMS center number affect iMessage?
No. iMessage travels over the internet through Apple’s servers, so it is untouched. The SMS center number only affects traditional green-bubble SMS and MMS texts.
Do I need to repeat this on every iPhone?
No. The number lives on the SIM card, so it follows the SIM to any phone. But if SMS breaks right after moving the SIM to a new iPhone, checking the stored number is a sensible first step.
Conclusion
The SMS center number is one of those invisible settings you never think about until it breaks. With three dialer codes — check, set, and reset — failed text messages are a one-minute fix, as long as you use your carrier’s official number. Anything else, your carrier can sort out remotely.
