If you received an error code 4750, it generally means the recipient’s carrier has rejected the message but didn’t provide a specific reason.
Possible reasons
The carrier's spam filter may have blocked the message.
The recipient may not be an active subscriber, have an inactive prepaid account, or have opted out of receiving SMS from this number.
The message may have been sent to an IoT device not configured to receive standard text messages.
A temporary issue with the recipient's handset could have prevented message delivery.
How to resolve
If the recipient wants to receive messages from this number, ask them to contact their carrier's support.
Ask the customer to retest by sending a message. Handset issues can be temporary.
If the issue persists, please open a ticket and provide more details (message content, time of day, etc.) so we can investigate further.