[Asterisk-Users] No sound when dialing out over SIP Proxy

[Kib Eki]

Hi,

i have trouble to dial out over my sip-provider gmx.

I can register with my provider over port 5060 and also dial out.
It rings at the remote phone but when the call is answered there is no 
sound / voice to hear.

This is the part from my sip.conf and extensions.conf:
register => 12345:12345 at sip-gmx.net
[gmx-out]
 type=peer
 secret=12345
 username=12345
 host=sip.gmx.net
 fromuser=12345
 fromdomain=sip.gmx.net
 disallow=all
 allow=alaw
 allow=ulaw
 allow=g729

exten => _0.,1,Dial(SIP/${EXTEN:1}@gmx-out)

Thanks,
kib