Asterisk wont accept PSTN Call w/ 1 digit extensions

i do calling from pstn into asterisk and i can hear IVR is asking for extension no. when i press “0” for operator nothing happend until it get busy.
meanwhile when i press 3-digit extensions such as 321 i am connected to that channel.

stranged!!! isnt it?

here is my dial plan

[general]
static=yes
writeprotect=no
autofallthrough=yes
clearglobalvars=no
priorityjumping=no

[globals]
CONSOLE=Console/dsp ; Console interface for demo
TRUNK=Zap/g1 ;PSTN = Channel 1-8
RECEPTIONIST=Zap/9 ;Receptionist = Channel 9
PHONE_10=Zap/10 ; = Channel 10
PHONE_11=Zap/11 ; = Channel 11
PHONE_12=Zap/12 ; = Channel 12
PHONE_13=Zap/13 ; = Channel 13
PHONE_14=Zap/14 ; = Channel 14
PHONE_15=Zap/15 ; = Channel 15
PHONE_16=Zap/16 ; = Channel 16
PHONE_17=Zap/17 ; = Channel 17
PHONE_18=Zap/18 ; = Channel 18
PHONE_19=Zap/19 ; = Channel 19
PHONE_20=Zap/20 ; = Channel 20
PHONE_21=Zap/21 ; = Channel 21
PHONE_22=Zap/22 ; = Channel 22

SIP_1=SIP/kerberos
SIP_2=SIP/anton

[incoming]
include => internal

exten => s,1,Wait(3)
exten => s,2,Answer()
exten => s,3,Background(silence/1)
exten => s,4,Background(enter-ext-of-person)
exten => 1,1,Goto(internal,271,1)
exten => 1,2,Goto(incoming,s,1)
exten => 2,1,Goto(internal,251,1)
exten => 2,2,Goto(incoming,s,1)
exten => 3,1,Goto(internal,231,1)
exten => 3,2,Goto(incoming,s,1)
exten => 4,1,Goto(internal,302,1)
exten => 4,2,Goto(incoming,s,1)
exten => 5,1,Goto(internal,331,1)
exten => 5,2,Goto(incoming,s,1)
exten => 6,1,Goto(internal,351,1)
exten => 6,2,Goto(incoming,s,1)
exten => 7,1,Goto(internal,921,1)
exten => 7,2,Goto(incoming,s,1)
exten => 8,1,Goto(internal,941,1)
exten => 8,2,Goto(incoming,s,1)
exten => 0,1,Goto(internal,0,1)
exten => 0,2,Goto(incoming,s,1)
exten => i,1,Playback(pbx-invalid)
exten => i,2,Goto(incoming,s,1)
exten => t,1,Playback(vm-goodbye)
exten => t,2,Hangup()

[internal]
include => macro-voicemail
;include => macro-outbound-local
;include => outbound-long-distance

exten => 0,1,Macro(voicemail,${RECEPTIONIST})
exten => 201,1,Macro(voicemail,${PHONE_10})
exten => 202,1,Macro(voicemail,${PHONE_11})
exten => 203,1,Macro(voicemail,${PHONE_12})
exten => 231,1,Macro(voicemail,${PHONE_13})
exten => 251,1,Macro(voicemail,${PHONE_14})
exten => 271,1,Macro(voicemail,${PHONE_15})
exten => 301,1,Macro(voicemail,${PHONE_16})
exten => 302,1,Macro(voicemail,${PHONE_17})
exten => 331,1,Macro(voicemail,${PHONE_18})
exten => 333,1,Macro(voicemail,${PHONE_19})
exten => 351,1,Macro(voicemail,${PHONE_20})

;GYM
exten => 801,1,Answer()
exten => 801,2,Dial(${PHONE_21},30)
exten => 801,3,Playback(vm-nobodyavail)
exten => 801,4,Hangup()

;Guardhouse
exten => 123,1,Answer()
exten => 123,2,Dial(${PHONE_22},30)
exten => 123,3,Playback(vm-nobodyavail)
exten => 123,4,Hangup()

;SIP
exten => 334,1,Macro(voicemail,${SIP_1})
exten => 321,1,Macro(voicemail,${SIP_2})

;Retrieve voicemail
exten => 888,1,Answer()
exten => 888,2,VoiceMailMain(@yykredit_voicemail)
exten => 888,3,Hangup()

;conference
exten => 8000,1,Goto(conf,1)
exten => conf,1,Set(MEETME_RECORDINGFILE=/tmp/Tutorial-$ {TIMESTAMP})
exten => conf,2,Meetme(8000|sr)
exten => conf,3,Hangup()

exten => 1337,1,Goto(count,1)
exten => count,1,MeetMecount(1234|USERS)
exten => count,2,NoOp(Total: ${USERS} users)

exten => 555,1,Directory(our_voicemail,internal,f)
exten => 444,1,Directory(our_voicemail,internal)

exten => _9NXXXXXX,1,Dial(${TRUNK}/${EXTEN:1})

[macro-voicemail]
exten => s,1,Dial(${ARG1},20)
exten => s,2,Goto(s-${DIALSTATUS},1)
exten => s-NOANSWER,1,Voicemail(u${MACRO_EXTEN}@our_voicemail)
exten => s-NOANSWER,2,Goto(incoming,s,1)
exten => s-BUSY,1,Voicemail(b${MACRO_EXTEN}@our_voicemail)
exten => s-BUSY,2,Goto(incoming,s,1)
exten => _s-.,1,Goto(s-NOANSWER,1)
;exten => a,1,VoicemailMain(${MACRO_EXTEN}@our_voicemail)