I followed the instructions on the video by KF5JIM. The phones can call each other and the phones ring BUT you can't talk. I get a hangup. 

Here is a portion of the Asterisk log with the error. Any idea how I can correct this? I read the wiki page but I'm not sure what I should do next.

I forgot to mention that FreePBX was working great on my home network. The phones stopped talking to each other when I connected to the Mesh network. 

I figured it out -- actually I found a similar problem on Stack Exchange and there was an answer to a similar problem and  that fixed my problem.

The answer was to check the file /etc/asterisk/sip_nat.conf and be sure it was set like:
localnet=192.168.1.0/255.255.255.0

Well that is wrong for the Mesh but my file contained absolutely nothing -- it was blank.

I opened up the file and put in:
localnet=10.64.68.2/255.255.255.248

I then rebooted the system and now it WORKS!! I'm getting voice over my Raspberry PI/FreePBX system!!

I don't understand how Asterisk could ring the phones but not complete the call but this seems to be an important file that in my case needed to be updated.'

Mike N9MS