Why is RCS not working?

RCS almost never fails because of the network. All four US carriers carry it, so when chat features will not turn on the cause is nearly always the handset or the line: the wrong messaging app, a secondary SIM, a number still registering after a port, a rooted or work-managed device, or an iPhone on iOS 17 or earlier. Toggling RCS chats off and back on in Google Messages, then letting the number re-verify, fixes the majority of cases.

RCS Not Working? Six Fixes, In Order

Fix it on Android

Google Messages is the only Android RCS client on US networks, so every step below assumes it. Work through them in order and stop when the status changes to Connected.

Confirm you are in Google Messages and it is the default. Since AT&T retired Advanced Messaging and Samsung discontinued Samsung Messages in July 2026, a legacy app will report no support because it genuinely has none left. Install Google Messages from the Play Store, open it, and accept the prompt to make it your default messaging app.
Check the status screen. Tap your profile icon, then Messages settings, then RCS chats. The line at the top reads Connected, Setting up, or an error. That single line tells you whether you have a registration problem or a delivery problem, and the rest of these steps only apply to the first.
Confirm you have a real data connection. Registration needs mobile data or Wi-Fi at least once. Wi-Fi calling is not a substitute, and a phone that has been offline since setup will sit unregistered indefinitely.
Check which SIM is default. RCS registers against one SIM. On a dual-SIM or eSIM handset the setting follows the default data SIM, so the other line reads as unsupported even on a fully capable network. Switch the default data SIM to your messaging line if they differ.
Verify the phone number shown is yours. Under RCS chats the app displays the number it registered. After a SIM swap this occasionally still shows the old one, which produces messages that appear to send and never arrive.
Allow 24 hours after a port or activation. Registration runs after the port completes. During that window the status genuinely reports unavailable and there is nothing to fix.
Toggle it off and back on. In RCS chats, turn the toggle off, wait a few seconds, turn it back on, and let the number re-verify without switching apps.
Clear the app cache and restart. If it is still stuck after a full day, go to Android Settings, Apps, Messages, Storage, and clear the cache but not the data. Restart the phone and let it register from a stable connection.

Fix it on iPhone

Apple added RCS in iOS 18, so the first thing to check is the OS version under Settings, General, About. Anything earlier has no RCS to enable and no setting to find.

Open Settings, tap Apps, then Messages. Confirm RCS Messaging is switched on.
Check your carrier. RCS on iPhone arrives through a carrier bundle. All four US networks support it, but a prepaid brand or smaller MVNO may still be waiting on the update from its host network.
Toggle RCS Messaging off and on and give it a few minutes to re-register.
Remember iMessage is separate. A thread with another Apple user stays on iMessage regardless. RCS only affects conversations with non-iMessage contacts, so a blue thread behaving normally tells you nothing about whether RCS is working.

Cases where it will not work at all

Some situations are refusals by design rather than faults. Rooted devices and some managed enterprise work profiles are declined at registration, because the verification step cannot trust the handset. An iPhone running iOS 17 or earlier has no RCS to enable. A few smaller regional carriers and prepaid brands are still catching up, though most inherit support from whichever network they ride on. In each of these the status will not change no matter how many times you toggle it, and the honest answer is that the line cannot register rather than that something is broken.

When the problem is the other person

RCS is negotiated between both ends. If your status reads Connected and one particular thread still behaves like SMS, the recipient is the constraint: they are on an older iPhone, a non-RCS app, a device that cannot register, or they have RCS switched off. Nothing on your side will change that thread, and the message still arrives as SMS. Group threads drop to MMS for everyone the moment one participant cannot take RCS.

If you are the sender, not the recipient

For a business this is the argument against depending on RCS alone. A share of any list will always be mid-port, on an old client, or on a handset that cannot register, and none of that is visible before you send. The answer is fallback rather than exclusion: a well-built RCS programme delivers as RCS where the device is capable and drops to SMS automatically where it is not, so the message lands either way and only the presentation changes. If the channel itself is new to you, what RCS messaging is sets out what it can and cannot guarantee on a real list.

Key facts

The carrier is rarely the cause; all four US networks carry RCS.
Google Messages is the only Android RCS client on US networks since July 2026.
RCS follows the default data SIM, so a second line can read as unsupported.
A ported number can take up to 24 hours to register, which is normal.
Rooted devices, some work profiles, and iOS 17 or earlier cannot register at all.
A single thread behaving like SMS while your status reads Connected is a limit on the recipient side, not yours.

Frequently asked

Why did RCS stop working after it was fine before?

The usual causes are a change to the line rather than to the phone: a port, a SIM swap, a new eSIM becoming the default data SIM, or a plan change with an MVNO. A messaging app update that reset the default app does it too. Registration is per line, so anything that alters which number the app registers against will drop RCS until it re-verifies.

Does turning RCS off and on again actually fix anything?

Often, yes. The toggle forces a fresh registration handshake with the carrier network, which is what a stalled or half-completed registration needs. It is not a placebo step. What it cannot fix is a device that is refused registration outright, such as a rooted handset, or a line still mid-port.

Can my carrier see why RCS is not working on my line?

Only partly. Carriers can confirm whether the plan and line carry RCS and whether a port has finished, which covers a real share of cases. They generally cannot see handset-side causes such as the wrong default app, a VPN blocking registration, or the wrong default data SIM, so a support call is worth making after the handset checks, not before.

Is RCS not working the same as a message failing to send?

No, and the difference matters. If RCS is unavailable the message still sends, as SMS or MMS, and still arrives. What you lose is read receipts, typing indicators, image quality, and encryption. A message that genuinely fails to send is a network or account problem rather than an RCS one.