Why Does an SMS Fail to Be Sent?

There are many possible causes for SMS sending failures. In terms of the service procedure, typical failure scenarios can be:

1. The API fails to be called. That is, the SMS platform returns a response with an error code when the SMS API is called to send an SMS. Handle the issue by referring to API Error Codes.
2. The API is successfully called. However, no status report is returned, and the mobile phone does not receive the SMS.
   • Dial the recipient number to check whether the number is dead or suspended or the device is powered off. The Message & SMS platform sends a status report within 72 hours.
   • The SMS content may trigger a carrier's manual review. Normally, manual review is triggered only once. If your SMS content repeatedly triggers a carrier's manual review and you want real-time SMSs, contact Huawei Cloud customer service and apply for review exemption. If the platform intercepts the SMS, you can configure such SMS templates as review-free with the permission of the operation manager. If a carrier intercepts the SMS, change the SMS content (by modifying template variables or applying for a new template) to avoid sensitive words.
3. The API is successfully called, and the status report indicates that the SMS fails to be sent. Handle the issue by referring to SMS Status Error Codes.
4. The API is called successfully, and the SMS status report displays DELIVRD, indicating that the SMS is successfully sent. However, the mobile phone does not receive the SMS.
   • Check whether the SMS is intercepted to the junk box.

   • Check whether the phone has signal to receive other SMSs.

   • Check whether the inbox of the phone is full. If yes, delete some SMSs and then check whether new SMSs can be properly received.

   • Insert the SIM card on another phone for a test.

   • Restart the phone and check whether the SMS can be received.
5. Your account is in arrears. For the international SMS service, top up the account, and then the service is available. For the Chinese mainland SMS service, log in to the console, click Signature Management, and check whether the SMS signature needs to be activated. If the signature does not need to be activated, top up your account to use the service. If the signature is deactivated, click Activate to submit the activation application to the operation manager for review. The signature can be used after being approved.
6. In mode 2 (suspension upon resource package runout), the resource package quota may be occupied by failed SMSs in a short period of time due to the charging latency. As a result, subsequent SMSs sending fails, but the available quota is not affected.