If you received an error code 4750, it means the recipient’s carrier has rejected the message but didn’t provide a specific reason.
Possible reasons
The message may have been identified as spam or sent to an IoT device not configured to receive standard text messages.
An issue with the recipient's handset may have prevented message delivery.
For AT&T traffic, the recipient may be a prepaid user whose account is out of money or a subscriber who has opted out of receiving 10DLC and short code messages.
Actions to resolve
Avoid sending spam or fraudulent traffic. For additional tips on avoiding spam filtering, see our Messaging deliverability FAQ.
Handset issues can be temporary. Retest by sending the message again.
For AT&T traffic, ask the recipient to contact AT&T Support to turn off 10DLC and short code blocking if they want to receive messages from your number.
Troubleshooting
If the issue persists, please open a ticket with Bandwidth Support and provide more details (message content, time of day, etc.) so we can investigate further. For the full list of messaging error codes, please see our dev docs.