Sometimes, when users send out text messages, the recipient will say they have not received it. Users also, on their end, could wonder why they have not been responded to after sending an important text message to a lead or to their agent.
Issues that can impact SMS Text Delivery:
The Phone Number Can't Accept Texts
Reviewing our logs, there are many instances of SMS texts that are blocked for a variety of reasons such as:
- The phone number is for a landline phone that does not accept calls
- The cell phone is turned off
- The phone number is not valid
First, note that telecommunications carriers like AT&T and Verizon have implemented carrier filtering on SMS texts to:
- Enforce rules or regulations about what types of messaging are allowed to that country or mobile network
- Protecting mobile subscribers from unwanted messaging such as spam, fraud, or abuse
There is no standard practice for carrier filtering across all carriers. Filtering can range from a simple static list of prohibited terms, to advanced machine learning systems that constantly adapt based on the messages passing through them. Regardless of the system, carriers keep their filtering systems closely guarded secrets. Due to the ambiguous nature of these filtering mechanisms, Twilio is unable to say definitively how these systems work, or why a particular message was filtered.
Steps to Troubleshoot
- Check the phone number to determine whether it is a mobile number or not:
- Here is a tool to look up the type – wireless or not, and carrier of phone numbers: https://freecarrierlookup.com/.
- If the number is identified as wireless, meaning mobile, that number should be able to receive text messages.
- If the phone number is confirmed to be for a mobile, it is possible they did not get the message if their phone was turned off or if their carrier is having an issue.
- Please email us the recipient phone number(s) and the timeframe to firstname.lastname@example.org and the Brokerkit Help Desk team will pull the logs for texts sent to that phone number for further analysis and report back to you.