Transmission

Hi everyone
I'm porting transmission on an embedded system
and I am stuck on announce to tracker; when I announce to tracker(add torrent and stop torrent) I get tracker response as following

Got announce response: connected:1 timeout:0 seeders:1586 leechers:385 downloads:-1 interval:1800 min_interval:0 tracker_id_str:none pex:0 pex6:0
err:none warn:none
[BT] in function(onTrackerResponse) file(torrent.c) line(546)

when I announce to tracker(start torrent) I get tracker response as following

Got announce response: connected:1 timeout:0 seeders:-1 leechers:-1 downloads:-1 interval:0 min_interval:0 tracker_id_str:none pex:0 pex6:0
err:none warn:none
[BT] in function(onTrackerResponse) file(torrent.c) line(546)

It seems that I my CURL works fine and connect to tracker; following are my debug prints; but I can't get peer list from tracker
pex number always is a big fat zero, I check almost all information but cannot figure out, can anybody help me ? thanks in advance.

!!!!connected
[CURL] in function(Curl_connecthost) file(connect.c) line(955)
[CURL] in function(setup_conn) file(url.c) line(4754)
[CURL] in function(addHandleToSendOrPendPipeline) file(multi.c) line(2171)
[CURL] in function(multi_runsingle) file(multi.c) line(959)
[CURL] in function(multi_runsingle) file(multi.c) line(1138)
[CURL] in function(multi_runsingle) file(multi.c) line(1148)
[CURL] in function(Curl_do) file(url.c) line(5023)
[CURL] in function(Curl_http) file(http.c) line(2060)
[CURL] in function(Curl_http) file(http.c) line(2137)
Host: torrent.ubuntu.com
[CURL] in function(Curl_http) file(http.c) line(2527)
HTTP/1.1
User-Agent: Transmission/2.61
Host: torrent.ubuntu.com:6969
Accept: */*

thank you for your reply, very appreciate
the flow of calling transmission api is same as cli(aommand line)
but instead of calling tr_torrentStart() ; we call tr_torrentStop,
and up to user to choose start then call tr_torrentStart()

quote "That (stop response) should be followed by a start response with the peer list."

Do you mean that we shouldn't call stop and let user choose to start?
Is this flow wrong ?
and I modify my code(base on 2.61) to 13573, but still the same.
Thanks you very much