Detecting dial status

I am having trouble with asterisk detecting dial status…

I have a TA-X100P connected to an extension of a Panasonic 1232. That way I can dial an extension of the 1232 form a sip phone.

Zapata.conf has callprogress=yes

and I have the following dial plan:

exten => _1XX,1,Dial(Zap/g1/${EXTEN},15)
exten => _1XX,2,NoOp,${DIALSTATUS}
exten => _1XX,3,VoiceMail,u${EXTEN}
exten => _1XX,4,Hangup
exten => _1XX,102,VoiceMail,b${EXTEN}
exten => _1XX,103,Hangup

When I ring an extension of the 1232 with a sip phone the connection is established but asterisk thinks nobody picked, even though I can speak.

After a while asterisk starts the voicemail and reports the error “Nobody picked up in 15000 ms”.

Any ideas what I am missing?