I understand that you have noticed Pinpoint sending duplicate SMS messages to some users, even though API was called only once.
Pinpoint service does not send multiple copies of same SMS message. Pinpoint SMS service, instead, relays messages to downstream provider and phone carrier. In oder to investigate this issue, we need to troubleshoot based on your specific scenario. Since we cannot discuss account specific troubleshooting on re:Post, we suggest to reach out to AWS Support with specific details, including message ids and timestamp of duplicate messages.
Pinpoint, SMS not received (Vietnam)asked 3 months ago
The best AWS service for sending SMS via REST API callsasked 6 months ago
Chime SMS via APIasked 7 days ago
AWS Pinpoint seems to be sending multiple copies of the same SMS (though API was called just once)asked 6 months ago
Unable to send SMS through AWS SNS?asked 5 days ago
AWS SNS Text Messaging(SMS) did not deliver message to intended user even though the status is SUCCESSasked 2 months ago
Some SMS return with status: " Phone has blocked SMS"asked 3 months ago
Pinpoint SMS - International Usageasked 4 months ago
Pinpoint not receiving SMSasked 8 months ago
Our users are receiving multiple copies of the same email that we just sent onceasked 4 months ago