Learn why your users might receive duplicate SMS messages.
Several reasons can cause a handset to receive duplicate messages. In most cases, duplication of messages occurs when handsets are on the edge of reception and fail to send an acknowledgement that a message has been successfully received. Therefore, the message is retried.
How to resolve duplicate SMS messages
There are several ways to resolve this issue, and due to the variety of combinations of the handset and home networks, we suggest attempting multiple methods if the problem persists.
- Move to an area where reception is better
- Reconnect the device to the mobile network by switching in and out of flight mode
- Try your SIM card in another phone to eliminate handset issues
- Switch from 5G or 4G to 3G or 2G as these have a greater reception range
- On pay-as-you-go devices, some users have reported success with disabling/enabling balance notifications
On rare occasions, duplicate messages can be caused by a fault on the network, and this can be investigated following unsuccessful attempts with the previously mentioned troubleshooting steps. If you are still receiving duplicate messages after following these steps, contact support.
It is also possible that duplicate messages are in fact multiple messages submissions of the same message instead of the same message that gets duplicated. This can be caused by errors in CMS systems and Web Service/API integrations that we can help resolve.