[Asterisk-Users] cannot dial extensions

[AEG]

hi all, was wondering if someone could assist with a slight problem
i'm having. I have asterisk setup with extensions 101 to 109 and am
using xlite, grandstream budgetone, polycom ip500 and a couple of
other phones. the problem is:

1. only the xlite extension (107) can receive calls.
2. all extensions can dial into voicemail and get mwi when msgs are received.
3. when dialing a non-xlite extension (from any ext), it goes straight
to voicemail.
4. if i repoint 109 (cisco ata) to dial another ext as follows, the
call goes through:

[extension-test3]
exten => 109,1,Answer
exten => 109,2,Dial(SIP/103,20,ntr)
exten => 109,3,Voicemail,u107

otherwise it doesn't even pause at all. straight to vm. i'm suspecting that
there is a minor config issue somewhere in the conf files. the basic config is:

[extension-test3]
exten => 107,1,Answer
exten => 107,2,Dial(SIP/107,40,ntr)
exten => 107,3,Voicemail,u107

all extensions are listed the same.

Any ideas would greatly appreciated.