SMS Delivery Issues – Failed & Undelivered Messages (Outgoing SMS from Growth99)
Understand why an outgoing SMS message may fail or remain undelivered when sent from Growth99 in clear, non-technical language, so you can quickly understand what happened and whether any action is required.
Understanding Message Statuses
Undelivered
Messages that were successfully sent from Growth99 but did not reach the recipient’s device due to carrier or network-related issues. These are often temporary and may resolve automatically.
Failed
Messages that could not be sent at all due to invalid numbers, landline numbers, etc. These typically require corrective action.
Undelivered Message Reasons
|
Reason |
Explanation |
|
Provider Timeout Error |
The recipient’s phone was switched off, out of coverage, or had no signal at the time of delivery. |
|
Unknown Destination Handset |
The phone number is inactive, disconnected, or no longer exists. |
|
Message Filtered |
The carrier blocked the message due to content restrictions or spam-filtering rules. |
|
Unknown Error |
The carrier did not provide a specific reason, commonly due to a temporary network issue. |
|
Message Blocked |
The message was blocked because required messaging registration or compliance was not completed. |
|
Missing Message Segment |
A long message was split into multiple parts and one segment failed to deliver. |
|
Temporary Block (Fraud Detection) |
Messaging traffic was temporarily paused due to suspicious or unusual sending patterns. |
|
Delivery Temporarily Restricted |
Delivery was limited due to sender reputation or trust-score concerns. |
|
US A2P 10DLC – Daily Message Cap Reached |
The daily sending limit for registered business messaging was reached. |
|
Downstream Carrier Error |
The message was accepted by the mobile carrier, but the carrier failed to deliver it due to internal issues. |
|
Carrier Network Congestion |
High traffic on the carrier’s network caused delays or delivery failures. |
Failed Message Reasons
|
Reason |
Explanation |
|
Landline Number |
The destination number is a landline and cannot receive SMS messages. |
|
Invalid Number |
The phone number format is incorrect or the number does not exist. |
|
SMS Not Supported |
The destination number or carrier does not support SMS messaging. |
|
Message Queue Overflow / Timeout |
Too many messages were sent in a short period, exceeding system limits. |
|
Invalid Messaging Service SID |
Messaging service configuration is missing or incorrect. |
|
Authentication Error |
Account credentials or permissions are invalid. |
|
From Number Not SMS Enabled |
The sending number is not enabled for SMS messaging. |
|
Attempt to Send to Unsubscribed Recipient |
The recipient previously opted out by replying STOP. |
|
Permission to Send SMS Not Enabled for the Region |
SMS sending is not enabled for the destination country or region. |
Best Practices to Minimize SMS Issues
- Use valid, mobile-enabled phone numbers
- Complete the required business messaging registration and compliance
- Avoid sending large message volumes in a short time
- Respect contact’s opt-out requests at all times
- Keep message content clear, relevant, and professional
Need Help?
If you experience repeated issues with SMS delivery or need help looking through your messaging setup, the Growth99 Support Team is here to help.
Email: support@growth99.com