Quick Answer
What should you do when an SMS or MMS fails?
Open the affected message in Conversations and review its status or error details. The error code can help identify whether the problem involves the recipient's number, media size, carrier filtering, sending rate, messaging capabilities, or registration requirements such as 10DLC or toll-free registration.
Fixing Message Delivery Issues Without Guessing What Went Wrong
You may see an SMS or MMS fail or remain undelivered, but without clear feedback it can be difficult to know why it happened.
When a message fails, BizStackPro can show a status, such as failed or undelivered, and often an error code. These codes point toward the likely cause of the delivery problem.
Depending on the error, the issue may involve media size, carrier filtering, messaging compliance or registration, an invalid or unreachable phone number, message length, or sending pace.
Without understanding the status and error code, troubleshooting becomes trial and error. Reading the available error details first gives you a more useful starting point for deciding what to check and what to change.
Start with the failed message
In Conversations, open the message thread and hover over or open the details for the failed message to review the available error code and recommended next step.
Messaging Troubleshooting at a Glance
Before You Begin
Capture the error information first so you can troubleshoot the actual problem instead of changing several things at once.
- Open the failed or undelivered message in Conversations.
- Record the exact error code shown for the message.
- Confirm the recipient's phone number and country code.
- Determine whether the message was SMS or MMS.
- Check whether the same error is affecting one recipient or multiple recipients.
- Review your 10DLC or toll-free registration status when the error indicates a registration or compliance problem.
Quick Troubleshooting Checklist
Use these checks to narrow down the cause before making larger changes to your messaging setup.
Validate the Number
Check the recipient's phone number formatting, country code, and whether the destination is a mobile number rather than a landline.
Review the Message Content
Check the message for restricted categories, misleading claims, spam-like formatting, or other content that may contribute to carrier filtering.
Check MMS Media Size
If the message includes an attachment, compress or resize large images or videos and keep the media within the applicable size restrictions.
Review the Sending Rate
Avoid sending messages too quickly. High-volume sending can contribute to queue or carrier throttling issues.
Confirm Messaging Registration
If you use 10DLC or toll-free messaging, confirm that the required registration or campaign approval has been completed.
Look for patterns
If the same error code appears across multiple recipients, the problem may involve compliance, content, registration, or sending rate rather than a single contact's phone number.
Common LC Phone Messaging Error Codes
Match the error shown on the failed message with the entries below to identify the likely cause and an appropriate next step.
Capture the code before troubleshooting
If a message shows as failed, open its details and record the error code. Then compare the code against the relevant part of your sending setup, including number type, registration status, media size, content, and message pace.
Messaging Troubleshooting Best Practices
Frequently Asked Questions
What should I do if I encounter Error 11751 - Media Size Limit?
How can I fix Error 30001 - Queue Overflow?
What steps should I take for Error 30003 - Unreachable Destination Handset?
How do I address Error 30032 - Toll-Free Registration Pending?
Continue Learning
Continue learning how to manage SMS communication and troubleshoot messaging activity with these related BizStackPro Help Center guides.
