Sending Fax using API only send first page (Cover page)

Am sending faxes using the API in Sandbox. Am using curl in my app and have sent to a variety of fax machines/services. It is always only sending partial faxes with just the first page. Sending directly from the API reference on ringcentral site also does the same thing so the issue isn't how my app is programmed.

Office API Reference | RingCentral Developers