Voicemail contains only ringing sound

I have received for the second time a voicemail from Asterisk, about 2 minutes in duration, where the recording only plays a phone ringing. The source number is 8302214600 (Number obscured):

[May 20 15:49:44] VERBOSE[31441] logger.c:   == CDR updated on DAHDI/4-1
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [22@ivr-3:1] ExecIf("DAHDI/4-1", "0|dbDel|") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [22@ivr-3:2] Set("DAHDI/4-1", "__NODEST=") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [22@ivr-3:3] Goto("DAHDI/4-1", "from-did-direct|22|1") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Goto (from-did-direct,22,1)
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [22@from-did-direct:1] Macro("DAHDI/4-1", "exten-vm|22|22") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:1] Macro("DAHDI/4-1", "user-callerid") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:1] Set("DAHDI/4-1", "AMPUSER=8302214600") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:2] GotoIf("DAHDI/4-1", "0?report") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: GotoIf
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:3] ExecIf("DAHDI/4-1", "1|Set|REALCALLERIDNUM=8302214600") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: ExecIf
[May 20 15:49:44] DEBUG[31441] func_db.c: DB: DEVICE/8302214600/user not found in database.
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:4] Set("DAHDI/4-1", "AMPUSER=") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] DEBUG[31441] func_db.c: DB: AMPUSER//cidname not found in database.
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:5] Set("DAHDI/4-1", "AMPUSERCIDNAME=") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:6] GotoIf("DAHDI/4-1", "1?report") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Goto (macro-user-callerid,s,10)
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: GotoIf
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:10] GotoIf("DAHDI/4-1", "0?continue") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: GotoIf
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:11] Set("DAHDI/4-1", "__TTL=64") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:12] GotoIf("DAHDI/4-1", "1?continue") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Goto (macro-user-callerid,s,19)
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: GotoIf
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-user-callerid:19] NoOp("DAHDI/4-1", "Using CallerID "8302214600" <8302214600>") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Noop
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Macro
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:2] Set("DAHDI/4-1", "RingGroupMethod=none") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:3] Set("DAHDI/4-1", "VMBOX=22") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:4] Set("DAHDI/4-1", "EXTTOCALL=22") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] DEBUG[31441] func_db.c: DB: CFU/22 not found in database.
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:5] Set("DAHDI/4-1", "CFUEXT=") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] DEBUG[31441] func_db.c: DB: CFB/22 not found in database.
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:6] Set("DAHDI/4-1", "CFBEXT=") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:7] Set("DAHDI/4-1", "RT=20") in new stack
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: Set
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-exten-vm:8] Macro("DAHDI/4-1", "record-enable|22|IN") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-record-enable:1] GotoIf("DAHDI/4-1", "1?check") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Goto (macro-record-enable,s,4)
[May 20 15:49:44] DEBUG[31441] app_macro.c: Executed application: GotoIf
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Executing [s@macro-record-enable:4] AGI("DAHDI/4-1", "recordingcheck|20100520-154944|1274388577.557") in new stack
[May 20 15:49:44] VERBOSE[31441] logger.c:     -- Launched AGI Script /var/lib/asterisk/agi-bin/recordingcheck
[May 20 15:49:44] VERBOSE[31441] logger.c:   recordingcheck|20100520-154944|1274388577.557: Inbound recording enabled.
[May 20 15:49:44] VERBOSE[31441] logger.c:   recordingcheck|20100520-154944|1274388577.557: CALLFILENAME=20100520-154944-1274388577.557

Can anyone help me understand what is happening here?