Hello Asterisk users :-) Server: Asterisk 11.7.0~dfsg-1ubuntu1 on Raspberry Client: Zoiper on Android device If "Transport=tcp" everything works fine, without any trouble. If "Transport=tls" registration is fine. But after a few minutes, the peer continuously is "reachable...unreachable". ------ [2016-02-04 11:00:38] NOTICE[2179]: chan_sip.c:29427 sip_poke_noanswer: Peer 'android1' is now UNREACHABLE! Last qualify: 9 -- Registered SIP 'android1' at 192.168.10.22:41270 [2016-02-04 11:01:26] NOTICE[20576]: chan_sip.c:23522 handle_response_peerpoke: Peer 'android1' is now Reachable. (7ms / 6000ms) [2016-02-04 11:04:35] NOTICE[2179]: chan_sip.c:29427 sip_poke_noanswer: Peer 'android1' is now UNREACHABLE! Last qualify: 28 -- Registered SIP 'android1' at 192.168.10.22:48515 [2016-02-04 11:05:27] NOTICE[20670]: chan_sip.c:23522 handle_response_peerpoke: Peer 'android1' is now Reachable. (17ms / 6000ms) [2016-02-04 11:09:38] NOTICE[2179]: chan_sip.c:29427 sip_poke_noanswer: Peer 'android1' is now UNREACHABLE! Last qualify: 43 -- Registered SIP 'android1' at 192.168.10.22:52955 [2016-02-04 11:10:03] NOTICE[20737]: chan_sip.c:23522 handle_response_peerpoke: Peer 'android1' is now Reachable. (49ms / 6000ms) ------ The same happen with two other devices. TCP is fine, TLS is not. As a test, I configured two accounts on the same device with identical parameters, except one is TLS and the other is TCP. The result is the same: TCP is fine, TLS is intermittent. Any idea? Thanks for any hint Frank [android1] type=peer callerid="Abcd Efgh" <+1234567890> nat=force_rport,comedia qualify=6000 host=dynamic secret=qt528frh3bAW3 tcanreinvite=no context=venomphone call-limit=2 transport=tls encryption=yes