Attachments: Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.
I have had the same issue and while working with support they told me the receiver is hanging up. I spoke with the receiver and they are using a stand alone fax machine that has no issues receiving from others. I have also tested sending from another online fax account and it works every time. Something is up with RingCentral's faxing service. This has been on going since March 2022, starting then the result is either unknown or busy. If you get this resolved please come back here with the fix!
Why answer the question if you are "not familiar" with it? I am getting this a lot lately to a number of numbers, and when I call the fax lines, they are beeping and ready to get the fax. SO, knowing what "Unknown" is would help me know how to resolve this issue.
"Unknown" usually appears when the fax is still trying to send, especially if those are multiple pages.
I'm having the same issue and need confirmation that the faxes are going through. These faxes have a 24 hour response time and it is important to know if the faxes are successful or not.
7 People are following this question.
Custom Fax Covers on new Desktop App?
Auto reply acknowledgment for fax received
Incoming Fax Setting
Fax: Deliver fax to multiple extension users (or e-mail address)
Restrict incoming fax and allowing outgoing
Team messaging, video meetings and phone - all in one app.
Get the new RingCentral app