Subject / Title:
Inbound calls ring 6–7 times before AI agent answers
Message:
Hello Retell Support,
I’m experiencing a persistent delay with my Retell inbound US phone number. Incoming calls ring approximately 6–7 times before the AI agent answers. I would like the call to be answered around the 2nd or 3rd ring.
The agent is already configured with:
AI speaks first
Pause Before Speaking: 0s
A custom welcome message
I also reviewed the PCAP from one of the affected calls. The packet capture shows that Retell responds approximately 1 second after receiving the SIP INVITE. This suggests that the 6–7 ring delay is occurring before the call reaches Retell, somewhere in the upstream carrier / telephony routing path.
Retell Ask AI also confirmed that this behavior points to a possible carrier-to-carrier signaling delay, origination/routing configuration, DID provisioning/porting path, or another upstream carrier-side delay.
Could your team please review the carrier/routing configuration for my inbound number and determine why the SIP INVITE is reaching Retell only after several rings?
My goal is for inbound calls to reach the Retell agent quickly enough that the AI answers around the 2nd or 3rd ring.
I can provide the specific phone number, Call ID, PCAP file, and timestamps privately if needed.
Hello Shah-Fazal, just following up on this issue. The inbound phone number is now giving callers a busy signal and the AI agent does not answer at all. This is currently preventing us from receiving inbound customer calls. Please let me know if your team has any update on the Call ID investigation or the phone number routing. Thank you.
Hello Shah-Fazal, good morning. I’m following up again because the issue is still active this morning. The inbound number is still giving callers a busy signal and the AI agent is not answering at all. This is now affecting real customer calls. Please escalate this to the telephony team and let me know if there is any update on the Call ID investigation or the phone number routing. Thank you.
@promobusinessflorida I’ve escalated your issue to the team, but I don’t have any further information or updates yet. I’ll get back to you as soon as I hear back from them.
Hello Shah-Fazal, I understand the issue has been escalated, but I want to emphasize the urgency. The inbound number is still not working and callers are receiving a busy signal, so I am currently losing real customer calls and potential business. Please let the telephony team know this is a production-impacting issue and, if possible, prioritize the investigation. Thank you.
Good morning Shah-Fazal, I’m following up again because the inbound number is still not working and we are still losing customer calls. Since this issue has been ongoing since yesterday and is affecting active business operations, could you please provide an update from the telephony team or an estimated resolution time? Thank you.
@promobusinessflorida sorry you’re still losing live inbound — busy signal after the ring delay is a production-breaker, especially if you’re Florida-based.
I’ve done a lot of Retell inbound telephony triage (DID/carrier path vs agent answer latency). From your PCAP note (Retell ACK ~1s after INVITE) the multi-ring delay really does look upstream of the agent; the busy signal then usually means the DID/trunk is rejecting or not binding to the inbound agent at all.
If Retell support is still waiting on telephony, I can do a short paid diagnostic Zoom: confirm number assignment + inbound agent binding, carrier/port path, and whether you need a temporary failover number so calls stop dying while they investigate. Florida-friendly hours.
Hello @promobusinessflorida We looked into the call and found that the delay is occurring before the call reaches Retell.
The number the caller is dialing, +17862479xxx, is a T-Mobile number that forwards to your Retell number, +17863042xxx, after a no-answer timeout. The SIP signaling confirms that the call reaches our side only after that timeout has completed. Once the INVITE reaches Retell, the agent answers normally, consistent with the ~1-second timing you observed.
To avoid the delay, you could either:
Have callers dial the Retell number (+17863042xxx) directly, or
Change the forwarding on the T-Mobile number to forward immediately rather than after several rings.
If immediate forwarding isn’t possible, reducing the T-Mobile no-answer timeout may also help.
So, there isn’t a Retell/Twilio routing change needed here: the delay is caused by the forwarding behavior on the T-Mobile number.