Problem

Solution 

Open the FreePBX one_touch_recording.php and look for: 

//removing ,because we are handling mix monitor through dialpaln -> FREEPBX-14292 - mixMonPost not sending the varibles if there is a space in b/w.
//$astman->mixmonitor($masterChannel, "{$mixMonDir}{$year}/{$month}/{$day}/{$callFileName}.{$mixMonFormat}", "ai(LOCAL_MIXMON_ID)$beep", $mixMonPost, rand());

Uncomment the second line. The code may look slightly different depending on your version, simply remove the two "/" characters at the start of the line to uncomment.

//removing ,because we are handling mix monitor through dialpaln -> FREEPBX-14292 - mixMonPost not sending the varibles if there is a space in b/w.
$astman->mixmonitor($masterChannel, "{$mixMonDir}{$year}/{$month}/{$day}/{$callFileName}.{$mixMonFormat}", "ai(LOCAL_MIXMON_ID)$beep", $mixMonPost, rand());

The modification will cause the one_touch_recording.php script to initiate recordings. This is required to use iSymphony integration with the FreePBX one touch recording feature. If you would prefer to opt out of one touch recording entirely and use iSymphony recording strategy see: Recording Source/Destination Extension Incorrect