SNS is unable to send SMS to a specific Telecom?

Question

Hello. We are sending OTP via SMS. However, Dito Telecome in the Philippines keeps failing with the message "Unknown error attempting to reach phone".

Customers keep contacting us saying they can't receive SMS.

After checking the log, it seems that only DITO is causing the error.

What should we check?

{ "notification": { "messageId": "d5796878-acb6-52ce-xxxx-xxxxxxxxxx", "timestamp": "2024-09-24 01:33:46.709" }, "delivery": { "phoneCarrier": "DITO", "mnc": 66, "numberOfMessageParts": 1, "destination": "+63 xxxxxxxxx", "priceInUSD": 0.15885, "smsType": "Transactional", "mcc": 515, "providerResponse": "Unknown error attempting to reach phone", "dwellTimeMs": 22, "dwellTimeMsUntilDeviceAck": 5676 },
"status": "FAILURE"
}

Pandurangaswamy · Answer

**1. Verify Carrier Support**

* Check with your SMS provider (e.g., AWS SNS, Twilio, etc.) if DITO Telecom is fully supported for delivering SMS. Some telecom providers may not have proper agreements or technical connectivity with all carriers in a region.
* Verify the Mobile Network Code (MNC 66) and Mobile Country Code (MCC 515) for DITO in your provider’s coverage documentation.

**2. Contact Your SMS Provider**

Reach out to the support team of your SMS provider and share the specific error log

```
"providerResponse": "Unknown error attempting to reach phone"
```
The provider should have insights or logs on why the message is failing specifically for DITO, and whether they need to work with DITO to resolve connectivity or routing issues.

**3. Test with Alternative Providers**

Consider testing the SMS delivery with a different SMS provider to see if the issue persists with DITO Telecom. This helps determine whether the issue is specific to your current provider or a broader issue with DITO’s SMS handling.

**4. Check Phone Number Formatting**

Ensure that the phone numbers are formatted correctly (international format with country code). DITO Telecom might enforce strict formatting rules.

**5. Check Local Regulations or Restrictions**

In some cases, certain telecom providers in specific regions may impose restrictions on transactional or promotional messages. Ensure that your SMS traffic complies with local SMS regulations in the Philippines, particularly for DITO.

**6. Monitor DITO Telecom Status**

Check whether DITO Telecom is experiencing any network issues or outages that might be affecting SMS delivery. DITO’s network might be experiencing technical difficulties that could lead to intermittent delivery failures.

SNS is unable to send SMS to a specific Telecom?

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