We have been facing a problem that if there is more than 1 concurrent call, the assistant only starts responding to one of them and goes silent on all the other ones. What could be the possible causes? Relevant information: 1. Number hosted on Twilio. 2. It's a Hong Kong number. ```

I’ve seen this happen when concurrent Twilio calls share the same session or media stream, causing the assistant to only respond to one. I can help you check if each call is creating a unique session and if Twilio webhooks are mapped correctly. Do you see distinct call_sid values tied to separate assistant sessions in your logs? That will tell us if it’s on Twilio or assistant side. @optimusblack

@Vercel Yes, the call_sid in the logs at twilio are all distinct. One question: Is it possible that we may need to use a transient assistant? We are using the same assistant for all the calls

Since your call_sids are unique, the issue is most likely from using the same assistant across multiple calls. In practice, setting up a transient assistant for each call keeps the sessions separate and prevents responses from cutting off. I’ve worked through this setup before and can help you get it running smoothly. Let’s continue the details privately @optimusblack

Hi @Vercel thank you for your help. That was actually my thought as well (not great that VAPI doesn't say this clearly in the documentation). I started using transient assistants this morning and was going to report here but you beat me to it haha. It's all working now. Thanks again for your help