Firmware version: Any
Fax to email failed.
Tiff file not able to be open and it's size showing 0 bytes.
Asterisk CLI log shows:
[2019-04-02 13:56:31] WARNING: app_fax.c:1160 phase_e_handler: Error transmitting fax. result=48: Disconnected after permitted retries.
[2019-04-02 13:56:31] WARNING: app_fax.c:1695 transmit_audio: Loop finished, res=0
[2019-04-02 13:56:31] WARNING: app_fax.c:2133 transmit: Transmission failed
The FXO port signal shows CED tone PBX sent interfered the CNG tone from the line which makes the fax detection failed.
User has configured the TX volume with abnormal value of 200%. Decrease the TX volume to 80%, and later the fax to email works.