Incoming & outgoing calls ring well but drop on accept with AT^DDSETEX on Chan_Dongle trunk

Hi.

I am posting this after having tried almost everything I could to debug the problem for last 4-5 days. Hope to find help here.

I have an Asterisk13 setup with SIP extensions 200-299 and a Chan_Dongle trunk (CID 93885940). External number being called or originating incoming call is 064013357 (0 prefix for outgoing). Internal calls over SIP work seamlessly. However, while both outgoing calls and incoming calls on Chan_Dongle trunk ring well, they drop (incoming) or give a circuit busy (outgoing) message as soon as they are accepted. I have reviewed my dialplans to best of my ability, reviewed the trunk and outgoing/incoming route settings, also tried issuing ATD directly from asterisk CLI but the behaviour remains same.

Guess since it is my first post, I am not allowed to attach the log file (Link to error_log.txt). Sharing some of the warnings and error messages below too.

In an internal SIP extension to SIP extension call, the simple_bridge is joined followed by an iax2 channel establishing the connect followed by successful hangup. But the same call flow does not seem to be working with chan_dongle. I believe the channel establishment part is failing. Some of the warning messages may be indicating an error which I am unable to decipher. I have validated the dongle (E1750) - it supports voice calling, does not have any PIN or password to it. It works seamlessly on a windows box.

Currently I am just not sure if it is something minor in dialplan or config that is incorrect or if I have hit a bug. Since what I am trying is something basic, I suspect I have got it wrong somewhere. Appreciate any help or pointers to investigate. Thanks for your help.

/Rohit

Outgoing call from sip extension 200 via trunk chan_dongle

[2017-02-07 17:31:27] WARNING[24749] func_cdr.c: CDR requires a value (CDR(variable)=value)
[2017-02-07 17:31:27] ERROR[30759] at_response.c: [dongle0] AT^DDSETEX failed (This appears BEFORE call accepted but AFTER call starts ringing on external number)
[2017-02-07 17:31:44] ERROR[30759] at_response.c: [dongle0] answered incoming call with not exists call idx 4, hanging up! (This line appears AFTER call accepted but drops)
[2017-02-07 17:31:44] ERROR[30759] at_response.c: [dongle0] Command ‘AT+CLCC’ failed
[2017-02-07 17:31:48] WARNING[32165][C-00000005] channel.c: Prodding channel ‘SIP/200-00000008’ failed

Outgoing call on trunk chan_dongle routed to sip extension 200

[2017-02-07 17:33:21] WARNING[32241][C-00000006] chan_sip.c: This function can only be used on SIP channels.
[2017-02-07 17:33:21] WARNING[32241][C-00000006] Ext. 93885940: Friendly Scanner from
[2017-02-07 17:33:21] WARNING[32241][C-00000006] channel.c: [Dongle/dongle0-0100000003] Don’t know how to indicate condition 22
[2017-02-07 17:33:32] ERROR[32204] at_response.c: [dongle0] AT^DDSETEX failed (This appears AFTER call accepted at extension 200 but call drops)
[2017-02-07 17:33:32] ERROR[32204] at_response.c: [dongle0] answered incoming call with not exists call idx 4, hanging up!
[2017-02-07 17:33:32] ERROR[32204] at_response.c: [dongle0] Command ‘AT+CLCC’ failed

Anyone, any help please? Thx.