Why will my text messages not send?
A red exclamation mark, a message stuck on sending, or texts that go to some people and not others. Three different messaging systems share one app, and knowing which one failed tells you the fix.
- Difficulty
- beginner
- Time
- 25 min
- Read
- 5 min
Short answer
Look at what colour the message is and what the send button says, because that identifies which system tried. If only some people fail, it is one messaging system rather than your signal. Turning off the modern system for one conversation — sending it as a plain text message instead — is the fastest test and often the fix, and it costs nothing to try before restarting anything.
The messages app on a modern phone hides three separate systems behind one interface. Plain SMS goes through the mobile network and works anywhere with signal. iMessage goes over the internet between Apple devices. RCS goes over the internet through the mobile industry's newer standard, on both platforms now, and carries read receipts, typing indicators, better pictures and end-to-end encryption. The phone chooses between them silently per conversation, and each fails differently: SMS fails on signal, iMessage fails on Apple's servers or account state, RCS fails on registration with your network. A single failure therefore tells you a great deal if you notice which system was in use.
Step by step
- Notice whether it fails for everyone or just some people.Failing to everyone points at signal, the SIM, or the phone. Failing to specific people while others work means one messaging system is broken and the rest are fine — which immediately rules out signal as the cause.
- Read the colour and the label.On iPhone, blue is iMessage and green is SMS or RCS, and the send field says which. On Android, the Messages app labels the field "Text message" or "RCS message". That label is the single most useful piece of information on the screen.
- Try sending the same message as a plain text.Hold the failed message and look for "Send as Text Message" on iPhone, or turn RCS off for the conversation on Android. If it goes immediately, the fault is the newer system's registration, not your connection — and that is both the diagnosis and a workable stopgap.
- Check signal separately from data.SMS needs mobile signal and nothing else, and it works where data does not. iMessage and RCS need working internet. A phone on wifi with no mobile signal can send iMessages and cannot send a text, which confuses people badly.
- Check the message centre number if plain SMS fails to everyone.Every network has a message centre number stored on the phone, and a wrong or missing one stops every text going out while everything else works. It is buried in the messaging settings, network operators publish the correct value, and it is a genuine cause after a SIM change or a phone transfer.
- Restart the phone, then toggle flight mode.This re-registers the phone with the network and with the messaging services, which is exactly what is stuck in many cases. Do it before deeper changes, and give it a minute to reconnect fully.
- Re-register the internet messaging services if they are the problem.On iPhone, turn iMessage off, wait, and turn it back on — activation can take up to a day and needs both signal and internet. On Android, RCS can be turned off and on in the Messages app settings, which forces re-verification with your network.
- Check whether you have been blocked or barred.Messages to one specific person that never arrive, with no error, may be blocking at their end. Separately, an unpaid bill or a bar on premium and international messaging will stop specific categories of message — worth checking with the network if it is one number range.
Common mistakes
- Resetting the phone to fix messaging — It is a large response to something that is usually a per-conversation setting or a registration state. Reset network settings, which is much narrower, is the appropriate escalation if you get that far.
- Assuming full signal bars mean texts will send — Bars show signal strength, not registration or account state. A phone can show four bars and be unable to send anything because it has not registered for messaging, or the account is barred.
- Switching away from iPhone without turning iMessage off — Your number stays registered to iMessage and other iPhone users' messages go into it rather than to your new phone. Apple provides a deregistration page and it is worth doing before the switch, not after.
If it doesn't work
Red exclamation mark, "Not Delivered"
Cause: The send failed outright — Fix: Tap it and choose to send as a text message. If that works, the internet-based system was the problem; if it also fails, look at signal, the SIM and the account.
Stuck at "Sending" indefinitely
Cause: No working path out — Fix: Check signal and data separately. A phone showing bars but no data will hang a picture message or an RCS message forever while plain texts go fine.
Works to Android friends, fails to iPhone friends
Cause: iMessage state — Fix: This is the classic pattern after leaving iPhone with iMessage still registered to your number. Apple runs a deregistration page for exactly this, and it is worth using even years later.
Picture messages fail, text messages work
Cause: Picture messaging needs mobile data with a specific setting — Fix: Multimedia messages require mobile data even on wifi, and they need the network's messaging settings present. Turn mobile data on and check the messaging access point settings with your network.
All texts fail on a new SIM or a new phone
Cause: Message centre number missing — Fix: Enter the correct number for your network in the messaging settings. Networks publish this, and it is a two-minute fix for a total failure.
Texts to a short number or an overseas number fail
Cause: A bar on the account — Fix: Premium-rate and international messaging are often barred by default on pay-as-you-go and on child accounts. The network can lift it.
Questions people ask
Why do some of my messages cost money and others do not?
Plain SMS is charged by your network according to your plan; iMessage and RCS travel over the internet and use data instead. That is why a phone in a poor-signal area falls back to SMS and someone with an unlimited-texts plan and a small data allowance may prefer it to.
Do my texts still work if I have no data?
Plain SMS does — it uses the signalling channel of the mobile network and works where data does not, which is why emergency and network messages use it. Picture messages, iMessage and RCS all need data.
Why did my group chat suddenly split into separate conversations?
Usually because one participant's system changed — someone left iMessage, or an RCS group fell back to plain multimedia messaging. Mixed groups spanning both platforms are the least reliable case and the reason many households settle on a single messaging app instead.
Is there any way to know a text was actually delivered?
iMessage and RCS both show delivery and read status. Plain SMS mostly does not, though some networks support a delivery report you can turn on in the messaging settings. The absence of an error is not proof of delivery on plain SMS.