In a while there was a thread (cand find it) where one of the core FS developers mentioned that there always should be an Unique-ID field in the event, so if there is no Unique ID field it can be added. Below is the event with no Unique-ID Event received Event-Name: BACKGROUND_JOB Core-UUID: bae130be-6719-4854-a0ed-2fdbb2477a12 FreeSWITCH-Hostname: lab3 FreeSWITCH-Switchname: lab3 FreeSWITCH-IPv4: 192.168.100.11 FreeSWITCH-IPv6: %3A%3A1 Event-Date-Local: 2011-05-25%2002%3A56%3A20 Event-Date-GMT: Tue,%2024%20May%202011%2021%3A56%3A20%20GMT Event-Date-Timestamp: 1306274180052931 Event-Calling-File: mod_event_socket.c Event-Calling-Function: api_exec Event-Calling-Line-Number: 1424 Job-UUID: 26266606-d9b4-4c9d-9642-792f6912d160 Job-Command: originate Job-Command-Arg: %7BMT-fwd_dst_type%3D'Phone%20No',progress_timeout%3D15,MT-fwd_condition%3DALWAYS,originate_timeout%3D90,MT-fwd_oclid%3DTrue,MT-fwd_dst_tech%3DNUM,MT- fwd_timeout%3DNone,leg_timeout%3D60,origination_caller_id_number%3D433777100,MT-fwd_dst%3D901055490,origination_uuid%3D67829d64-918f-4ecf-8ece-e0b391d05172%7D%5Bsip_h_ X-MT-fwd_dst_tech%3DNUM,sip_h_X-MT-fwd_timeout%3DNone,sip_h_X-MT-fwd_condition%3DALWAYS,continue_on_fail%3Dfalse,leg_a_uuid%3D9c3e5ca3-4081-4cde-8316-6dbd4a1d021c,sip_ h_X-MT-fwd_dst_type%3D'Phone%20No',sip_h_X-MT-fwd_dst%3D901055490,sip_h_X-MT-fwd_oclid%3DTrue%5Dsofia/gateway/fs_local/sip3779050%20%26park Content-Length: 27 -ERR INVALID_NUMBER_FORMAT