Can you take a snapshop of the information found under "call status"?
You can just obtain this by pointing your browser to the Obi IP address, and
clikcing on "call status" on the top left side of the screen.
I have intermittently seen this in my case (over the past 2 years of usage of multiple
Obis) and I haven't been able to fully resolve. However,
couple thing that really helped though in my case:
+ I configured the Obi with a static IP address, and not using DHCP.
To avoid the possibility for my router to hand out the same IP address to another device
in the home network, I "reserved" the IP address I gave to the Obi based on its MAC address
on the router as well.
+ I setup explicitly port forwarding rules in my firewall/nat router so that the client SIP ports
mapped to my obi, get delivered to the right device (I hit this problem actually when I turned on
2 obis in the same network and forgot to reassign the SIP address and as a result the wrong SIP
request was delivered to the wrong obi). In any case, even if you only have a single Obi, it doesn't
hurt to do this: its a good defensive approach.
My guess would be that there is conflict in IP address assignment within your home network after a while. And as such the firewall may or may not be able to send incoming traffic to the right device.
The fact that you say that it works for a while and then it exhibits the behavior you describe,
kind of points to this as a cause.
L.
PS. Notice that I said earlier I haven't been able to fully resolve this. What happens some times,
is that a call seems to be established properly, the remote side hears me, I don't hear anything,
and when I check the "call status" it shows that the remote end IP address for the call is
set to 0.0.0.0. Some times the only way I could restore proper functionality was to reboot the obi.
But the problem is so infrequent that I can't even file a bug with Obihai given that it cannot
be reproduced at will.