T.38 problems - RTP Read too short

[sharkbitz]

I have a strange issue, and this is only happening on outbound fax terminations using Cisco SPA112's (I have tried another SPA and the problem persists, even at different locations). If I send a fax directly on asterisk using the SendFAX application, I don't have this problem. Inbound faxes always work, using the same hardware and same carrier, same SPA. The problem also occurs when I tried a different carrier. I have experimented with the directmedia setting, but it did not help.

The server has no bandwidth issues, and 0 packet loss. I am running Asterisk 11.8.1 on Centos.

t38pt_udptl = yes,redundancy,maxdatagram=400

Any advice would be appreciated.

Console verbose was OFF and is now 99999.
SIPX*CLI> udptl set debug on
UDPTL Debugging Enabled
== Using SIP RTP CoS mark 5
-- Executing [2293382415@TESTLDOUT:1] Dial("SIP/sipfax1-00000105", "SIP/12293382415@carrier,60,tT") in new stack
== Using SIP RTP CoS mark 5
-- Called SIP/12293382415@carrier
-- SIP/carrier-00000106 is making progress passing it to SIP/sipfax1-00000105
> 0x7fa4dc03aff0 -- Probation passed - setting RTP source address to 292.199.242.86:19346
> 0x7fa4ec0e15f0 -- Probation passed - setting RTP source address to 292.252.127.94:16418
-- SIP/carrier-00000106 answered SIP/sipfax1-00000105
== Using UDPTL CoS mark 5
== Using UDPTL CoS mark 5
UDPTL (SIP/carrier-00000106): packet from 292.199.242.86:19346 (seq 0, len
UDPTL (SIP/sipfax1-00000105): packet to 292.252.127.94:16418 (seq 0, len 6)
UDPTL (SIP/carrier-00000106): packet from 292.199.242.86:19346 (seq 0, len
UDPTL (SIP/sipfax1-00000105): packet from 292.252.127.94:16418 (seq 0, len 6)
UDPTL (SIP/carrier-00000106): packet to 292.199.242.86:19346 (seq 0, len 6)
[Apr 23 14:59:07] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:07] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:07] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
UDPTL (SIP/sipfax1-00000105): packet from 292.252.127.94:16418 (seq 1, len
UDPTL (SIP/carrier-00000106): packet to 292.199.242.86:19346 (seq 1, len
[Apr 23 14:59:09] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:09] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:09] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:13] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:13] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:13] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:15] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:15] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:15] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:20] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:20] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:20] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:22] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:22] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:22] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:26] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:26] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:26] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:28] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:28] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short
[Apr 23 14:59:28] WARNING[1473][C-00000071]: res_rtp_asterisk.c:3559 ast_rtp_read: RTP Read too short