# Janus answer SDP sometimes has no candidates **URL:** \ **Category:** General\ **Created:** [June 21, 2023, 7:57pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364 "2023-06-21T19:57:35Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Shannon](https://avatars.discourse-cdn.com/v4/letter/s/e19adc/32.png) [@Shannon](https://janus.discourse.group/u/Shannon)\ **Post date:** [June 21, 2023, 7:57pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/1 "2023-06-21T19:57:35Z")
Using Janus 1.1.3 for the Videoroom plugin, about 5-10% of the answers to publisher offers have no ICE candidates in the SDP. I have tried using full trickle for Janus, but I have never received the trickle event. I get the “local-candidate” events, but those appear to really just be for logging and not for use. In particular I see that the local-candidate events can be published but an extra conditional check in Janus can then exclude that candidate. This tells me not to rely on the local-candidate events. We are still in the testing phase, and most of the calls are identical in terms of the client media constraints & networking. The calls that do not include candidates in the answer are functionally identical to those that do include candidates. I have multiple questions: 1. When configured for full-trickle, what would keep Janus from sending trickle events? I am logging every event I receive from Janus, even if I am not acting on them, and I have never received a trickle event. 2. Using half-trickle, what is keeping Janus from including candidates? The STUN and TURN servers are local to the same network with extremely low latency. I don’t see anything in Janus server logs to indicate what went wrong when Janus omits candidates from the answer. 3. I can detect when the SDP does not have a candidate, and rather than providing that to the client, it looks like I can send a configure with the offer SDP again. Are there any special considerations for using that approach to recover when there are no candidates in the answer? Thanks in advance! ---
**Author:** ![lorenzo](https://yyz2.discourse-cdn.com/free1/user_avatar/janus.discourse.group/lorenzo/32/425_2.png) [@lorenzo](https://janus.discourse.group/u/lorenzo)\ **Post date:** [June 22, 2023, 1:30pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/2 "2023-06-22T13:30:18Z")
Missing candidates on the client side sound like client issues: so something you need to fix there, not Janus. Maybe no interfaces work for the purpose, or you need STUN/TURN? ---
**Author:** ![Shannon](https://avatars.discourse-cdn.com/v4/letter/s/e19adc/32.png) [@Shannon](https://janus.discourse.group/u/Shannon)\ **Post date:** [June 22, 2023, 1:51pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/3 "2023-06-22T13:51:34Z")
My apologies if I wasn’t clear with my question. I am talking about the Janus side. My client (via a signaling server) sends the offer, and the Janus answer is the one that sometimes does not have a candidate. The Janus answer does have the expected candidate(s) most of the time, but not always. That’s the scenario I need to be able to recover from automatically, and I’m hoping to send a configure message when I don’t see a candidate in the answer with the intention that it will create a new answer from Janus. For clarity, I am using TURN in both directions – mainly for limiting the number of ports to map through firewalls and other network appliances. I have Coturn installed on the same server with Janus in each server instance. I am using TURN REST API for credentials for the TURN server for Janus and the clients. I can see Janus request the credentials, I can see the TURN allocation succeed, and in 90% of the calls the relay candidate is provided by Janus in the answer to the publisher offer. In these calls, I can see in the Janus admin page that the remote candidates from the client are listed for that publisher handle, but no local candidates. Yet nothing I see in the Janus logs indicates why Janus doesn’t think it has its own local candidate. I would love to have insight into the cause, but most important to me is how I can automatically retry to recover, thus question 3 about whether I am assuming correctly that sending a configure message is valid. I would normally try so I can see if it works, but I cannot reproduce the situation at-will. ---
**Author:** ![lorenzo](https://yyz2.discourse-cdn.com/free1/user_avatar/janus.discourse.group/lorenzo/32/425_2.png) [@lorenzo](https://janus.discourse.group/u/lorenzo)\ **Post date:** [June 23, 2023, 8:26am UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/4 "2023-06-23T08:26:28Z")
You should check Janus logs then. I’d say the lack of TURN candidates may be due to a timeout of some sort, but at least the host candidates should be there. If those aren’t either, my guess is you have a network interface that’s not responding properly at times. Or maybe you configured a too small RTP range in `janus.jcfg` and all ports are taken sometimes? ---
**Author:** ![Shannon](https://avatars.discourse-cdn.com/v4/letter/s/e19adc/32.png) [@Shannon](https://janus.discourse.group/u/Shannon)\ **Post date:** [June 23, 2023, 1:30pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/5 "2023-06-23T13:30:53Z")
> [@lorenzo](#): > > Or maybe you configured a too small RTP range in `janus.jcfg` and all ports are taken sometimes? Thank you, I’ll look there! I know I had restricted the range during testing, and I never opened it back up. ---
**Author:** ![yvvarun](https://avatars.discourse-cdn.com/v4/letter/y/59ef9b/32.png) [@yvvarun](https://janus.discourse.group/u/yvvarun)\ **Post date:** [August 7, 2023, 9:53am UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/6 "2023-08-07T09:53:09Z")
hey @Shannon , i’m facing a similar issue. did you find any solution for this? ---
**Author:** ![maximoantinori](https://avatars.discourse-cdn.com/v4/letter/m/dec6dc/32.png) [@maximoantinori](https://janus.discourse.group/u/maximoantinori)\ **Post date:** [August 10, 2023, 12:05pm UTC](https://janus.discourse.group/t/janus-answer-sdp-sometimes-has-no-candidates/364/7 "2023-08-10T12:05:37Z")
> [@yvvarun](#): > > i’m facing a similar issue same problem me too…