I am unable to send SMS

I am using Zoom's premium service, which includes unlimited calling and SMS within the USA and Canada. While the calling functionality works perfectly, I have encountered difficulties with sending SMS messages. Every time I attempt to send a message, I receive an error notification, preventing the message from being sent.

As this feature is crucial for my business communication needs, I kindly request your assistance in resolving this issue promptly. Please help me and provide guidance on how to rectify the problem so that I can continue utilizing the full capabilities of the premium Zoom service. I pay USD 17 every month.