MiCollab NuPoint doesn't know fax was successful

[VeeDubb65]

We're just wrapping up deploying MiCollab with NuPoint and NuPoint fax. (I know, I know. It's 2021 and we're still faxing)

I can receive faxes without issue.

I can send faxes reliably, except for two problems.

1. I never get the confirmation email for a successful fax.
2. Every hour or so, it re-sends the same fax.

I do get an error report email if there's a problem that keeps the fax from working at all, so I know that email is functional.

It seems as though NuPoint can't tell the fax was successful, so it is keeping the fax in the queue and retrying.

Any idea what would keep nupoint from recognizing that the fax was successful?

[VeeDubb65]

Our Mitel support found the answer:

"The MiVB COS used for Nupoint ports on the MiVB has an FAX option named "Return Disconnect Tone" This option must be set to NO. When set to Y the MiVB will send a busy tone when it detects that the far end FAX has released the call. Most sending FAX machines respond to by clearing the call on their end so the port is not tied up. But Nupoint interprets this busy tone as a send failure and will retry sending again until the mailbox LCOS limit is reached."