AWS SNS transactional messages to send to Oman failure status . "Unknown error attempting to reach phone"

Question

"Unknown error attempting to reach phone"
"priceInUSD": 0.13783,
it costs me very high to send a message and it's failure .
I tried the promotional sometimes it sends and sometimes not and when it sent successfully it sends as "NOTICE"
note: I can't use sender ID of Oman since when I try to request originator identity for Oman it results to an error.
Validation Error Occurred - Reason="SENDER_ID_REQUIRES_REGISTRATION" Fields="isoCountryCode
I contacted support they said Oman doesn't require to be registered.
so I tried another country sender id but I got also error when I want to send test message
Resource Not Found - ResourceType="sender-id"

Mohamed Daoud · Answer

The $0.13783 failure cost indicates you're hitting premium route pricing for failed international delivery attempts. AWS charges even when carriers reject messages at the final hop.

The sender ID contradiction between the error message and support response is odd given that many GCC countries have tightened SMS rules in 2024. I suspect you need to register.

Proven Solutions (in order of effectiveness):
**1. Immediate Fix: Default Originator Test**
Remove your custom sender ID completely and test with AWS defaults:

{
  "PhoneNumber": "+968-----",
  "Message": "Test message",
  "MessageAttributes": {
    "AWS.SNS.SMS.SMSType": {
      "DataType": "String",
      "StringValue": "Transactional"
    },
    "AWS.SNS.SMS.MaxPrice": {
      "DataType": "String", 
      "StringValue": "0.05"
    }
  }
}

This bypasses sender ID registration entirely and should immediately improve delivery rates.

**2. Message Type Strategy**
Switch to Transactional for all Oman messages
Promotional messages are heavily filtered by Oman carriers (hence your "NOTICE" issue)
Transactional has higher priority routing and less filtering

**3. Phone Number Validation**
Ensure format is exactly: +968----
No spaces, dashes, or parentheses
Verify numbers are mobile (not landline)
Test with multiple Oman carriers (Omantel, Ooredoo)

**4. Escalate Properly with AWS**
Open a technical support case with:
Subject: "SNS SMS Oman Delivery - Sender ID Registration Discrepancy"
Request escalation to Middle East SMS specialists
Include your account ID, specific error messages, and cost impact
Ask for current Oman regulatory requirements documentation

Alternative Approaches if issues Persist is to look into AWS Pinpoint SMS as sometimes it has different carrier relationships than SNS and better delivery reporting and analytics

re:Post Agent · Answer

The issues you're experiencing with sending SMS messages to Oman through AWS SNS are complex and involve several factors:

1. Delivery Failures: The "Unknown error attempting to reach phone" message suggests there might be connectivity issues between AWS SNS and the mobile carriers in Oman. This could be due to carrier-specific restrictions, filtering mechanisms, or temporary network problems.

2. High Costs: The price you mentioned ($0.13783 per message) is indeed high, especially for failed deliveries. This highlights the importance of resolving the delivery issues to avoid unnecessary costs.

3. Inconsistent Delivery: The fact that promotional messages sometimes get through (appearing as "NOTICE") indicates that there might be issues with how transactional messages are being processed or filtered by Omani carriers.

4. Sender ID Registration: The error message you received about sender ID registration for Oman is confusing, especially since AWS support informed you that Oman doesn't require registration. This discrepancy needs further investigation.

5. Alternative Sender ID Issues: Your attempt to use a sender ID from another country also failed, which complicates the situation further.

To address these issues, consider the following steps:

1. Double-check with AWS support about the exact requirements for sending SMS to Oman, including any necessary registrations or approvals.

2. Review your message content to ensure it complies with Omani regulations and doesn't trigger any filters.

3. Try sending messages at different times of day to see if there are any patterns in successful deliveries.

4. Enable detailed CloudWatch logging for your SMS messages to gather more information about the delivery attempts and specific error codes.

5. Consider testing with an alternative SMS provider specifically for Oman to determine if the issue is AWS-specific or more general.

6. If possible, try sending to a variety of Omani phone numbers to see if the issue is widespread or limited to specific carriers.

If the problems persist, you may need to escalate the issue with AWS support, providing them with detailed logs and examples of failed messages. They might need to investigate potential routing or connectivity issues with their SMS providers for Oman.
      
**Sources**  
[SNS SMS "Unknown error attempting to reach phone" only for China Mobile numbers | AWS re:Post](https://repost.aws/questions/QURitjZCY1RHGUmh_Lbr-2pw/sns-sms-unknown-error-attempting-to-reach-phone-only-for-china-mobile-numbers)  
[SNS is unable to send SMS to a specific Telecom? | AWS re:Post](https://repost.aws/questions/QU0l_nBe9HQRGAY3rQJkPHHg/sns-is-unable-to-send-sms-to-a-specific-telecom)  
[AWS SNS can not send SMS to mobile phone | AWS re:Post](https://repost.aws/questions/QUVa9lqxT9SeWWTnuZvcrZvQ/aws-sns-can-not-send-sms-to-mobile-phone)

AWS SNS transactional messages to send to Oman failure status . "Unknown error attempting to reach phone"

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