Resolving Common SMS Delivery Issues
Introduction
Encountering an error when sending an SMS can be frustrating. This guide will help you understand why these errors occur, how to identify the specific issue, and the steps you can take to resolve them, ensuring your messages reach their intended recipients.
Why Do SMS Delivery Errors Happen?
SMS messages can fail to deliver for a variety of reasons. Common causes include the recipient's phone number being invalid or out of service, the contact having previously opted out of messages, carrier restrictions, or technical issues with the messaging service. When a message fails, the CRM provides a specific error code to help you diagnose the problem.
How to Find an SMS Error Code
To troubleshoot a failed message, you first need to locate the error code.
Step 1: Access the Conversation Logs
Navigate to the Conversations section within your CRM. Find the specific conversation containing the undelivered message.
Step 2: Identify the Error
Click on the failed conversation. A red triangle icon will indicate an error. Hovering over or clicking this icon will reveal a numerical error code and a brief description of the issue.
Common SMS Error Codes and Their Solutions
Here are explanations for some of the most frequent SMS errors you might see.
Error 21610: User Has Unsubscribed
Description: The recipient has replied with "STOP" to opt out of messages.
Solution: You must not send further messages to this number unless the contact initiates communication by sending "START". Ensure you have a clear opt-in process for your contacts.
Error 30003: Number Unreachable
Description: The recipient's phone is turned off, out of network coverage, or otherwise temporarily unavailable.
Solution: Try resending the message at a later time. Verify that the phone number is correct and active.
Error 30005: Inactive or Non-Existent Number
Description: The destination phone number is no longer in service or does not exist.
Solution: Attempt to send the message again after some time has passed. It is good practice to regularly clean your contact lists to remove invalid numbers.
Error 30006: Landline Number
Description: The number you are trying to message is a landline, which cannot receive SMS messages.
Solution: Remove this number from your SMS contact list. Use a phone number validation tool to identify landlines before sending messages.
Error 30007: Message Blocked by Carrier
Description: The mobile carrier blocked the message, often because the content was flagged as potential spam or violated their policies.
Solution: Avoid using spam-triggering words, shortened URLs, or excessive punctuation. For best deliverability, register your phone number for A2P 10DLC or Toll-Free verification.
Error 30034: A2P 10DLC Registration Required
Description: You are trying to send a message to a U.S. number from a 10DLC number that is not linked to an approved A2P campaign.
Solution: You must complete the A2P 10DLC registration process for your brand and campaign. After submission, it can take some time for approval. Ensure your phone number is linked to the approved messaging service.
Error 11751: Media File Too Large
Description: The file attached to your MMS message exceeds the maximum size limit allowed by the provider.
Solution: Compress or resize the media file. For messages to the US and Canada, the maximum size is typically 5MB.
General Troubleshooting Tips
- Verify Phone Numbers: Always ensure the numbers on your list are valid, active, and capable of receiving SMS.
- Check Account Status: Some errors indicate a problem with your underlying messaging service account. Confirm that your account is in good standing.
- Review Message Content: If messages are frequently blocked, review your content to ensure it is clear, personalized, and compliant with carrier guidelines.