I’m using the latest Openfire (3.6.4) with SIP Phone Plugin (1.0.5) on Spark (2.5.8).
The Openfire server, Asterisk server, and the client (me) are all on the same local network.
Using an softphone (X-lite) works like a charm, but with Spark, when I dial, it gets mute. When I recieve, it gets mute about 3, 4 seconds and then start to hear and talk normally.
With 2.6.0 beta2 I have similar problem where voice calls are muted for some reason, both incoming and outgoing. However with 2.5.8 all works fine with OpenFire 3.6.4 - Asterisk 1.6.10 - Trixbox 2.8.0.3
Well if I asume you have a sip hard phone with same symptoms, my suggestion would be to look up at dial plan in extensions.conf or within phone’s settings.