How to Fix WhatsApp We Couldn't Send an SMS to Your Number

You're trying to set up WhatsApp, but suddenly you hit a frustrating wall: "We couldn't send an SMS to your number." This common error stops millions of users from verifying their accounts, often without any clear explanation. Whether you're switching phones, reinstalling the app, or setting up WhatsApp for the first time, this issue can feel like a dead end. Fortunately, the causes are usually simple and fixable.

In this guide, we'll walk you through proven solutions step by step to fix WhatsApp we couldn't send an SMS to your number, so you can receive the code and get back to chatting in minutes.

Part 1. What Happened When WhatsApp Says "We Couldn't Send an SMS to Your Number"

When WhatsApp says "We couldn't send an SMS to your number", it usually means the app was unable to deliver the verification code to your phone via text message. This error can happen for several reasons.

• Incorrect Phone Number: You may have entered the wrong number or country code.
• Poor Network Signal: Your phone doesn't have a stable cellular connection, so the SMS can't be received.
• SMS Blocking: Some carriers or phones block automated SMS messages (especially if you are using Do Not Disturb, spam filters, or third-party SMS apps.)
• Airplane Mode or No SIM: If your phone is in airplane mode or doesn't have an active SIM card, SMS delivery will fail.
• Carrier or Network Issues: Your carrier may be experiencing issues or blocking short-code messages used by WhatsApp.
• App Permissions: On Android, if WhatsApp doesn't have permission to read SMS messages, it might trigger errors during verification.
• Outdated WhatsApp Version: Rarely, an outdated version of WhatsApp may cause verification problems.

Part 2. How to Fix WhatsApp We Couldn't Send an SMS to Your Number iPhone

Let's walk through a series of solutions, each building on the last, to help you troubleshoot thoroughly and effectively.

Fix 1. Double-Check Your Phone Number

Before diving into technical fixes, it's important to rule out the most basic issue: entering the wrong number. If your number is incorrectly formatted, WhatsApp simply won't be able to send anything.

Open your WhatsApp and ensure your country code is selected properly. You have entered your number without leading zeros or extra spaces. If the number is accurate and you still see the error, the next step is to make sure your phone can even receive SMS messages right now.

Fix 2. Check Signal Strength and SMS Functionality

WhatsApp sends the code via regular SMS. If your iPhone doesn't have a reliable signal or SMS capability at the moment, that message won't go through, even if your number is right.

Step 1. Open the Messages app and ask a friend to send you a regular text.

Step 2. If you don't receive it:

• Check for signal bars.
• Toggle Airplane Mode on and then turn it off.
• Restart your iPhone to refresh the network connection.

If your phone still isn't receiving texts, the issue may be with the SIM card or mobile service itself.

Fix 3. Make Sure the SIM is Active and Properly Inserted

Even if your phone shows some signal, the SIM may not be fully functional for sending or receiving SMS, especially if you are using a dual SIM setup or eSIM.

Go to Settings > Cellular to ensure your cellular line is enabled and show service bars and check that SMS is enabled for that line.

For dual SIM users, you can confirm the number you are using is set as the default line for SMS under Settings > Cellular > Default Voice Line.

Fix 4. Turn Off Focus Modes and Do Not Disturb

Even with a working SIM and signal, iOS's Focus Modes, especially Do Not Disturb and Sleep, can quietly block SMS or phone calls from unknown numbers, including WhatsApp's verification message.

Go to Settings > Focus and then disable Do Not Disturb, Sleep, and any custom Focus profiles. Once these modes are off, your iPhone should be free to receive all incoming messages.

Fix 5. Disable SMS Filtering and Third-Party Blockers

Some iPhones use SMS spam filters or third-party apps that can intercept or auto-block messages that seem automated, like WhatsApp's 6-digit code.

Step 1. Go to Settings > Messages > Unknown & Spam to disable any third-party SMS filters such as Truecaller, Hiya, or RoboKiller.

Step 2. Check for any security apps or VPNs that may restrict messaging features.

Fix 6. Switch Between Wi-Fi and Mobile Data

Although WhatsApp uses SMS over cellular, the app may rely on internet connectivity to trigger the SMS process. If there's a weak or unstable Wi-Fi or data connection, this could be the missing link.

Step 1: Try turning Wi-Fi OFF, then attempt verification on mobile data only.

Step 2: Alternatively, if you're on mobile data and it's spotty, switch to a stronger Wi-Fi network.

Fix 7. Try the "Call Me" Option

If WhatsApp can't deliver the SMS after several tries, it will offer a "Call Me" option - an automated phone call that reads the verification code aloud.

Step 1: On the verification screen, tap Call Me.

Step 2: Answer the call and write down the 6-digit code when prompted.

Fix 8. Wait and Try Again Later

Finally, if you've tried verifying too many times in a short span, WhatsApp may temporarily block further attempts for security reasons.

If you see a cooldown or lockout message, wait up to 24 hours before trying again. You can try the Call Me option instead if it becomes available sooner.

Fix 9. Fix Possible iOS System Issues

If you try all kinds of solutions above but still cannot receive a verification code, the problem may be not on WhatsApp and SIM card. iOS system issues on your iPhone may be the causes.

To solve the possible iOS system issues, you just need a professional iOS system repair tool, TunesKit iOS System Recovery. That is a proven useful repair software that can fix more than 150 iOS system issues, including Instagram not working on iPhone, iPhone green lines on screen, and WhatsApp not working on iPhone. When you don't know what to do to fix issues, TunesKit iOS System Recovery will give you a surprise.

Let's see how to use TunesKit iOS System Recovery to fix WhatsApp we couldn't send an SMS to your number.

Step 1 Connect iPhone to PC

Download and install the repair software on your computer (Mac or Windows PC). Connect your iPhone to that PC using a USB cable. Enter the software to select the iOS System Repair feature. Click the Start button to start the fixing process.

Step 2Select repair mode

The Standard Repair mode will fix the issue without data loss. The Deep Repair mode will fix deeper issues, but it will delete all your iPhone data.

Step 3Download firmware package

Your iPhone info will be shown on this window. Make sure that info is correct. Click the Download button to download a firmware package for your iPhone.

Step 4 Fix WhatsApp we couldn't send an SMS to your number

Finally, when the firmware package is downloaded, click the Repair button to officially repair the possible iOS system issues causing the WhatsApp problem on your iPhone.

Part 3. Conclusion

Experiencing the WhatsApp "We couldn't send an SMS to your number" error can be frustrating, but it's typically easy to fix. By checking your number, network, SIM, and phone settings, you can resolve the issue quickly. If you doubt that there are certain iOS system issues on your iPhone, TunesKit iOS System Recovery will help you fix them without data loss.