I set up 3CX on my Samsung Galaxy (I9100M) with Android 2.3.3. After setting up my profile to use an external SIP provider (iptel.org) I get the promising "On Hook" status. But when I dial a number it says "Calling" for about 2 or 3 seconds and then just goes back to the "On Hook" status without completeing the call. Did I miss something in the setup. What do I need to do to complete a call? Thanks.