[Freeswitch-users] Error for emails related to faxing

We have users who report email failures related to fax notifications. I'm digging for further information on how to reproduce the issue, but so far the only error in the FreeSWITCH log is: EMAIL NOT SENT, error [Cannot open tmp file In spandsp.conf.xml, spool-dir is set to /tmp. The directory exists and is world readable and writeable. fs_cli -x version returns: FreeSWITCH Version 1.10.5-release-17-25569c1631~64bit (-release-17-25569c1631 64bit) Any idea what would cause the EMAIL NOT SENT error?