# libmediasoupclient cannot receive connectWebRtcTransport response.

**URL:** <https://mediasoup.discourse.group/t/libmediasoupclient-cannot-receive-connectwebrtctransport-response/293>\
**Category:** mediasoup libraries\
**Created:** [September 27, 2019, 2:50am UTC](https://mediasoup.discourse.group/t/libmediasoupclient-cannot-receive-connectwebrtctransport-response/293 "2019-09-27T02:50:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![huangjingpei](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/huangjingpei/32/120_2.png) [@huangjingpei](https://mediasoup.discourse.group/u/huangjingpei)\
**Post date:** [September 27, 2019, 2:50am UTC](https://mediasoup.discourse.group/t/libmediasoupclient-cannot-receive-connectwebrtctransport-response/293/1 "2019-09-27T02:50:01Z")

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I use wss to connect the mediasoup server, then I call “getRouterRtpCapabilities”, “createWebRtcTransport”, “join”.  
When I received the corresponding createWebRtcTransport message, I saved the transportid, iceParameters, iceCandidates,  
Parameters such as dtlsParameters, and create a SendTransport object. Then CanProduce creates an audio track if there is audio, called Send\_transport\_-\>Produce, the problem is here:  
When I received the OnConnect callback, I sent the connectWebRtcTransport message, the parameters used were the parameters passed to me by OnConnect, and then I was waiting to receive the message, but I was unable to receive any messages.  
Can you help me figure out why?

this is my signals:

1. 

send msg: {“data”:{“consuming”:false,“forceTcp”:false,“producing”:true,“sctpCapabilities”:[“numStreams”,{“MIS”:1024,“OS”:1024}]},“id”:1416194,“method”:“createWebRtcTransport”,“request”:true}

recv msg:{“response”:true,“id”:8042989,“ok”:true,“data”:{“codecs”:[{“kind”:“audio”,“mimeType”:“audio/opus”,“clockRate”:48000,“channels”:2,“preferredPayloadType”:100,“parameters”:{},“rtcpFeedback”:[]},{“kind”:“video”,“mimeType”:“video/VP8”,“clockRate”:90000,“rtcpFeedback”:[{“type”:“nack”},{“type”:“nack”,“parameter”:“pli”},{“type”:“ccm”,“parameter”:“fir”},{“type”:“goog-remb”}],“preferredPayloadType”:101,“parameters”:{“x-google-start-bitrate”:1000}},{“kind”:“video”,“mimeType”:“video/rtx”,“preferredPayloadType”:102,“clockRate”:90000,“rtcpFeedback”:[],“parameters”:{“apt”:101}},{“kind”:“video”,“mimeType”:“video/VP9”,“clockRate”:90000,“rtcpFeedback”:[{“type”:“nack”},{“type”:“nack”,“parameter”:“pli”},{“type”:“ccm”,“parameter”:“fir”},{“type”:“goog-remb”}],“preferredPayloadType”:103,“parameters”:{“profile-id”:2,“x-google-start-bitrate”:1000}},{“kind”:“video”,“mimeType”:“video/rtx”,“preferredPayloadType”:104,“clockRate”:90000,“rtcpFeedback”:[],“parameters”:{“apt”:103}},{“kind”:“video”,“mimeType”:“video/H264”,“clockRate”:90000,“parameters”:{“packetization-mode”:1,“level-asymmetry-allowed”:1,“profile-level-id”:“4d0032”,“x-google-start-bitrate”:1000},“rtcpFeedback”:[{“type”:“nack”},{“type”:“nack”,“parameter”:“pli”},{“type”:“ccm”,“parameter”:“fir”},{“type”:“goog-remb”}],“preferredPayloadType”:105},{“kind”:“video”,“mimeType”:“video/rtx”,“preferredPayloadType”:106,“clockRate”:90000,“rtcpFeedback”:[],“parameters”:{“apt”:105}},{“kind”:“video”,“mimeType”:“video/H264”,“clockRate”:90000,“parameters”:{“packetization-mode”:1,“level-asymmetry-allowed”:1,“profile-level-id”:“42e01f”,“x-google-start-bitrate”:1000},“rtcpFeedback”:[{“type”:“nack”},{“type”:“nack”,“parameter”:“pli”},{“type”:“ccm”,“parameter”:“fir”},{“type”:“goog-remb”}],“preferredPayloadType”:107},{“kind”:“video”,“mimeType”:“video/rtx”,“preferredPayloadType”:108,“clockRate”:90000,“rtcpFeedback”:[],“parameters”:{“apt”:107}}],“headerExtensions”:[{“kind”:“audio”,“uri”:“urn:ietf:params:rtp-hdrext:sdes:mid”,“preferredId”:1,“preferredEncrypt”:false,“direction”:“recvonly”},{“kind”:“video”,“uri”:“urn:ietf:params:rtp-hdrext:sdes:mid”,“preferredId”:1,“preferredEncrypt”:false,“direction”:“recvonly”},{“kind”:“video”,“uri”:“urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id”,“preferredId”:2,“preferredEncrypt”:false,“direction”:“recvonly”},{“kind”:“video”,“uri”:“urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id”,“preferredId”:3,“preferredEncrypt”:false,“direction”:“recvonly”},{“kind”:“audio”,“uri”:“[http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time",“preferredId”:4,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“video”,“uri”:“http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time”,“preferredId”:4,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“audio”,“uri”:“http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01”,“preferredId”:5,“preferredEncrypt”:false,“direction”:“inactive”},{“kind”:“video”,“uri”:“http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01”,“preferredId”:5,“preferredEncrypt”:false,“direction”:“inactive”},{“kind”:“video”,“uri”:“http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07”,“preferredId”:6,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“video”,“uri”:“urn:ietf:params:rtp-hdrext:framemarking”,“preferredId”:7,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“audio”,“uri”:“urn:ietf:params:rtp-hdrext:ssrc-audio-level”,“preferredId”:10,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“video”,“uri”:“urn:3gpp:video-orientation”,“preferredId”:11,“preferredEncrypt”:false,“direction”:“sendrecv”},{“kind”:“video”,“uri”:“urn:ietf:params:rtp-hdrext:toffset”,“preferredId”:12,“preferredEncrypt”:false,“direction”:“sendrecv”}],"fecMechanisms](http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time%22,%22preferredId%22:4,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time%22,%22preferredId%22:4,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22audio%22,%22uri%22:%22http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01%22,%22preferredId%22:5,%22preferredEncrypt%22:false,%22direction%22:%22inactive%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01%22,%22preferredId%22:5,%22preferredEncrypt%22:false,%22direction%22:%22inactive%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07%22,%22preferredId%22:6,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22urn:ietf:params:rtp-hdrext:framemarking%22,%22preferredId%22:7,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22audio%22,%22uri%22:%22urn:ietf:params:rtp-hdrext:ssrc-audio-level%22,%22preferredId%22:10,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22urn:3gpp:video-orientation%22,%22preferredId%22:11,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D,%7B%22kind%22:%22video%22,%22uri%22:%22urn:ietf:params:rtp-hdrext:toffset%22,%22preferredId%22:12,%22preferredEncrypt%22:false,%22direction%22:%22sendrecv%22%7D%5D,%22fecMechanisms)”:[]}}

1. 

{“data”:{“consuming”:false,“forceTcp”:false,“producing”:true,“sctpCapabilities”:[“numStreams”,{“MIS”:1024,“OS”:1024}]},“id”:1416194,“method”:“createWebRtcTransport”,“request”:true}

recv msg:{“response”:true,“id”:1416194,“ok”:true,“data”:{“id”:“9c388c6d-d387-431a-adba-ad76b7c56df6”,“iceParameters”:{“iceLite”:true,“password”:“r5k7luk2kzwxmpllsa906n1f1khefmay”,“usernameFragment”:“qgzawlrtj23whcck”},“iceCandidates”:[{“foundation”:“udpcandidate”,“ip”:“192.168.1.100”,“port”:47644,“priority”:1076302079,“protocol”:“udp”,“type”:“host”}],“dtlsParameters”:{“fingerprints”:[{“algorithm”:“sha-1”,“value”:“3C:45:ED:23:15:F2:A6:9F:CC:42:9B:49:BF:E8:FC:4A:0F:F4:D0:F5”},{“algorithm”:“sha-224”,“value”:“F8:BF:DA:C7:AE:EB:BD:88:62:AD:C6:7C:75:08:01:8B:24:48:B0:F2:1C:02:DA:7F:2E:42:A9:37”},{“algorithm”:“sha-256”,“value”:“EE:08:05:84:84:63:7D:86:9D:42:85:07:2A:02:65:D8:2C:C6:EB:66:C4:2A:D6:90:F1:D7:88:90:57:D4:7F:EC”},{“algorithm”:“sha-384”,“value”:“86:D8:67:4A:91:67:9D:71:E6:EF:5E:83:DF:BE:9D:CE:14:B8:9C:FC:B1:80:EE:14:30:12:E8:79:0F:53:EE:92:D7:77:F2:2C:5D:0B:99:4A:9B:7C:16:D1:B1:9C:9D:DA”},{“algorithm”:“sha-512”,“value”:“1B:D0:43:E8:20:F4:13:C8:EF:62:EA:3E:E9:16:96:2F:03:DF:D5:12:E3:3C:4A:9E:CC:C9:63:B3:AE:58:F2:FE:87:61:26:6C:AE:A7:A1:DA:75:35:29:4F:7F:F0:B6:87:F8:8A:A8:39:0D:6E:1F:AE:DE:49:06:43:49:FF:6A:5C”}],“role”:“auto”},“sctpParameters”:{“MIS”:1024,“OS”:1024,“isDataChannel”:true,“maxMessageSize”:262144,“port”:5000}}}

1. send msg: {“data”:{“device”:{“flag”:“chrome”,“name”:“Chrome”,“version”:“75.0.3770.100”},“displayName”:“RSU”,“rtpCapabilities”:{“codecs”:[{“channels”:2,“clockRate”:48000,“kind”:“audio”,“mimeType”:“audio/opus”,“parameters”:{“minptime”:10,“useinbandfec”:1},“preferredPayloadType”:100,“rtcpFeedback”:[]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/VP8”,“parameters”:{},“preferredPayloadType”:101,“rtcpFeedback”:[{“type”:“goog-remb”},{“parameter”:“fir”,“type”:“ccm”},{“type”:“nack”},{“parameter”:“pli”,“type”:“nack”}]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/rtx”,“parameters”:{“apt”:101},“preferredPayloadType”:102,“rtcpFeedback”:[]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/VP9”,“parameters”:{“profile-id”:0},“preferredPayloadType”:103,“rtcpFeedback”:[{“type”:“goog-remb”},{“parameter”:“fir”,“type”:“ccm”},{“type”:“nack”},{“parameter”:“pli”,“type”:“nack”}]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/rtx”,“parameters”:{“apt”:103},“preferredPayloadType”:104,“rtcpFeedback”:[]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/H264”,“parameters”:{“level-asymmetry-allowed”:1,“packetization-mode”:1,“profile-level-id”:“42e01f”},“preferredPayloadType”:107,“rtcpFeedback”:[{“type”:“goog-remb”},{“parameter”:“fir”,“type”:“ccm”},{“type”:“nack”},{“parameter”:“pli”,“type”:“nack”}]},{“clockRate”:90000,“kind”:“video”,“mimeType”:“video/rtx”,“parameters”:{“apt”:107},“preferredPayloadType”:108,“rtcpFeedback”:[]}],“fecMechanisms”:[],“headerExtensions”:[{“kind”:“video”,“preferredId”:4,“uri”:“[http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time"},{“kind”:“video”,“preferredId”:6,“uri”:“http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07”},{“kind”:“audio”,“preferredId”:10,“uri”:“urn:ietf:params:rtp-hdrext:ssrc-audio-level”},{“kind”:“video”,“preferredId”:11,“uri”:“urn:3gpp:video-orientation”},{“kind”:“video”,“preferredId”:12,“uri”:“urn:ietf:params:rtp-hdrext:toffset”}]}},“id”:1389808,“method”:“join”,"request](http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time%22%7D,%7B%22kind%22:%22video%22,%22preferredId%22:6,%22uri%22:%22http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07%22%7D,%7B%22kind%22:%22audio%22,%22preferredId%22:10,%22uri%22:%22urn:ietf:params:rtp-hdrext:ssrc-audio-level%22%7D,%7B%22kind%22:%22video%22,%22preferredId%22:11,%22uri%22:%22urn:3gpp:video-orientation%22%7D,%7B%22kind%22:%22video%22,%22preferredId%22:12,%22uri%22:%22urn:ietf:params:rtp-hdrext:toffset%22%7D%5D%7D%7D,%22id%22:1389808,%22method%22:%22join%22,%22request)”:true}

(MediaSoupClient.cpp:32): recv msg:{“response”:true,“id”:1389808,“ok”:true,“data”:{“peers”:[{“id”:“6eegeq6k”,“displayName”:“Spewpa”,“device”:{“flag”:“chrome”,“name”:“Chrome”,“version”:“77.0.3865.90”}}]}}

1. 

OnConnect {“fingerprints”:[{“algorithm”:“sha-256”,“value”:“D8:98:FD:59:75:99:B6:8E:9F:C2:09:83:C4:1B:38:B8:00:E3:0D:41:7D:57:2D:E3:8B:A9:F5:8B:9D:6C:D0:89”}],“role”:“server”}

send msg: {“data”:{“dtlsParameters”:{“fingerprints”:[{“algorithm”:“sha-256”,“value”:“D8:98:FD:59:75:99:B6:8E:9F:C2:09:83:C4:1B:38:B8:00:E3:0D:41:7D:57:2D:E3:8B:A9:F5:8B:9D:6C:D0:89”}],“role”:“server”},“transportId”:“9c388c6d-d387-431a-adba-ad76b7c56df6”},“id”:8211622,“method”:“connectWebRtcTransport”,“request”:true}

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**Author:** ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)\
**Post date:** [September 27, 2019, 3:34am UTC](https://mediasoup.discourse.group/t/libmediasoupclient-cannot-receive-connectwebrtctransport-response/293/2 "2019-09-27T03:34:03Z")

</div>

This is not related to mediasoup nor to libmediasoupclient but to the WebSocket message exchange between the client and the server, and you are using the mediasoup-demo project for that.

No idea why you don’t get a response. Enable logs in the server to see if something happens. Anyway, this is not related to libmediasoupclient at all.

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**Author:** ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)\
**Post date:** [December 2, 2019, 11:10pm UTC](https://mediasoup.discourse.group/t/libmediasoupclient-cannot-receive-connectwebrtctransport-response/293/3 "2019-12-02T23:10:57Z")

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