Network problems?

dear community,

have this setup: = FreePBX on our Datacenter = Phones outside, connected via VPN to the Network

All my snom phones are connected without any problems.
but my cisco spa112 and my polcycom soundstation goes offline after a sporadic time.

then i get this message:
chan_sip.c:29804 sip_poke_noanswer: Peer ‘99’ is now UNREACHABLE! Last qualify: 15

but i have opened all ports (all protocols) between nd

Name/username Host Dyn Forcerport Comedia ACL Port Status Description
10/10 D No No A 54780 OK (45 ms)
20/20 D No No A 38739 OK (45 ms)
40/40 D No No A 50949 OK (46 ms)
50/50 D No No A 58168 OK (46 ms)
60/60 D No No A 5060 OK (46 ms)
99/99 D No No A 5060 UNREACHABLE
MAINTRUNK Yes Yes 5060 OK (1 ms)
9 sip peers [Monitored: 6 online, 1 offline Unmonitored: 0 online, 0 offline]

60 = polycom soundstation
99 = cisco spa112 adapter

where i have here the problems? my snom devices (10-50) are working fine without any problems.

how i can debug?

thank you very much

Look in the /var/log/asterisk/full log file and see if you can find the place where the phones are dropping off-line. That should give you your first clue.

Also, the SPA112 should be in NAT mode, and a STUN server wouldn’t hurt.

In the case of SPA and Cisco, the extension needs to have NAT=YES.

If NATing is the issue, your phones may be sending and register, but the response gets lost, so it all falls apart shortly after.