Issue: When using the PHP SDK to send SMS messages, sending to a single recipient works fine. However, attempting to send to multiple numbers results in the following error:
Business operation is not supported.
Cause: Currently, the API restricts SMS messages to a single recipient per request to prevent unsolicited SMS messages.
Solution: If you need to send SMS messages, ensure that you only include one recipient per API request. You can find the official API documentation for sending SMS here: RingCentral SMS API Documentation
Using High Volume SMS API: If you need to send SMS messages to multiple recipients externally, consider using the High Volume SMS API. This API is designed for bulk messaging and allows you to send messages to multiple recipients efficiently. Refer to the documentation for more details: High Volume SMS API Documentation
