It looks like ICE is not the problem, but the DTLS handshake. (*)
2016-06-08 00:57:46.195948 [INFO] switch_core_media.c:6721 Skipping RTCP ICE (Same as RTP)
2016-06-08 00:57:46.195948 [INFO] switch_rtp.c:3328 Activate RTP/RTCP audio DTLS client
2016-06-08 00:57:46.195948 [INFO] switch_rtp.c:3459 Changing audio DTLS state from OFF to HANDSHAKE
When it fails, it doesn't go beyond the last line.
I updated openssl to v1.0.2h, rebuilt FS, but problem remains.
(*) I occasionally get SIP 488, but that's another story.
Regards,
Carlos