[Help] SIP not recognizing busy lines

[Bradrose]

Hi,

SIP is not recognizing busy lines. It just goes to the unanswered.

exten => _XX,1,Dial(SIP/${EXTEN},)
exten => _XX,2,voicemail,u${EXTEN}
exten => _XX,102,voicemail,b${EXTEN}
exten => _XX,103,hangup

any suggestions

Thanks
Brad