📱 3 Checkpoints When an SMS Doesn't Arrive
SMS messages use a different communication channel from email and are usually received through the Messages (SMS) app.
On both Android and iPhone, they do not appear in an email inbox.
Still, it’s quite common for users to say that an SMS message “didn’t arrive” or “can’t be found.”
In many cases, the message was delivered, but couldn’t be located due to the recipient’s app settings or configuration differences.
Below are the three main points to check when an SMS can’t be found.
① Check the “Messages (SMS)” App, Not the Email App
SMS messages are separate from email (e.g., Gmail).
💬 Look for the speech bubble icon—that’s the “Messages” app used for SMS.
✉️ Opening the envelope icon (email app) will not display SMS messages.
② Check the “＋Message (Plus Message)” App
If you’re using a device from Japanese Carriers docomo, au, or SoftBank,
you may have the ＋Message (Plus Message) app pre-installed.
When this app is set as the default SMS handler,
incoming SMS messages may appear there instead of the regular SMS folder.
If you see a blue speech bubble icon labeled “＋Message,” open it and check your inbox there.
③ Check for International SMS Blocking Settings
Some carriers block SMS messages received through international routes,
which are sometimes used by global SMS services such as Xoxzo.
On certain devices, this restriction is enabled by default.
How to fix it:
- Open “Messages settings” or “Advanced settings” on your phone.
- Look for options such as “Block international SMS” or “Block unknown senders.”
- Temporarily disable those settings and try receiving the message again.
💬 If It Still Doesn’t Arrive
- When messages are sent via global SMS routes, temporary delays on the carrier’s system may occur.
- In some cases, you can contact your carrier’s support and ask them to check the delivery logs for the SMS message.
🔊 Alternative Option: Voice Call Authentication
If SMS delivery is difficult—or if the user only has access to a landline instead of a mobile phone—
voice call text-to-speech authentication can be used as an alternative.
Adding this option broadens accessibility, improves convenience,
and may even enhance the overall value of your service.
Xoxzo provides a Voice API that can automatically read out verification codes.
Each call costs about 10 JPY.
For more information, see the Xoxzo Voice API documentation.
✅ Summary
| Checkpoint | Description |
|---|---|
| Are you checking the email app? | SMS messages are received via the “Messages” app, not the email app. |
| Checked the Plus Message app? | On some carrier devices, SMS may appear in the Plus Message app instead. |
| Is international SMS blocking enabled? | Temporarily disable this setting and try again. |
Related Links
Aiko Yokoyama
Customer Success and Operations
Joined January 2014. Experienced as a clerk in Foreign Trading company, started and maintained an online supplement store. Lived in overseas for 15 years. Looking forward to communicating our customers with the broad view based on those experience.
