My app has been working for over a year and now every outgoing fax is returning a status of "Unknown" and then being automatically retried 5 minutes / 10 minutes later with a result of "Unknown". Using the the fax by email functionality to the same test number and using the same test attachment, it always works with a result of "Sent".

The app uses the PHP SDK (https://github.com/ringcentral/ringcentral-php).

I can't find a decent log to help troubleshoot this issue. Anyone have any clues where to look? All responses from RC show the fax has a status of 'Queue'. Then progresses to 'Unknown' without any error messages. I have tried multiple fax numbers as well -- all with the same result.