Am also getting calls drop after 8 seconds. This happens between Express Talk terminals on different machines and also when a call is initiated via a Grandstream device incoming into the PABX routed through to a softphone.
Axon is installed on W2003 R2 server. My server access is via a wireless link, but this should cause problems as everything alse works OK.
Am unable to get unanswered calls to answer at the CallAttendant/VoiceMail either, but will be happy to get calls working first.
Thanks in anticipation.