Hi!
I am experiencing an issue with my inbound call configuration.
After setting up a phone number to be handled by a Retell AI agent, I am unable to receive calls.
The problem:
- When calling the configured number, the line returns a busy signal immediately.
- The number does not appear to be successfully registered or active within the Retell platform dashboard.
My configuration:
- Termination URI:
sip.messagenet.it:5060
- Credentials: SIP Trunk Username and Password have been correctly entered.
- Inbound Agent: V1 - DIVA TLC Autorisponditore
Troubleshooting performed: I have verified the credentials with my provider and they are correct.
It seems there might be a handshake or registration issue between Retell and the SIP proxy.
Could you please check the logs for my account to see if the registration attempt is being rejected or if there is a configuration mismatch on the Retell side?
Thank you for your assistance.
Best regards,
Davide
Based on your configuration, here are several areas to verify for your inbound SIP trunk setup:
Phone Number Format
Ensure your phone number is imported in E.164 format, which includes the country code prefixed with a plus sign (+), followed by the number with no spaces or special characters(1). For example, an Italian number should be formatted as "+39123456789"(1).
Termination URI Configuration
Your Termination URI should include the sip: prefix(2). The correct format should be sip:sip.messagenet.it:5060(2).
For inbound calls, you may also need to specify the transport method by appending it to the URI(2):
- For TCP:
sip:sip.messagenet.it:5060;transport=tcp(2)
- For UDP:
sip:sip.messagenet.it:5060;transport=udp(2)
- For TLS:
sip:sip.messagenet.it:5060;transport=tls(2)
Authentication Configuration
When importing your number via the Import Phone Number API, you need to supply the username and password in the sip_trunk_auth_username and sip_trunk_auth_password fields(3). Double-check that your SIP trunk credentials match exactly what’s configured with your provider(3).
Origination Settings
For inbound calls, you need to configure the origination settings in your SIP trunk provider to point to Retell’s SIP server(2):
- Retell SIP server URI:
sip:sip.retellai.com(2)
- IP block for traffic:
18.98.16.120/30 (All regions)(2)
Your provider needs to route inbound calls to Retell’s SIP server, not the other way around(2).
Common Disconnection Reasons
If calls show as dial_busy, this indicates the number dialed is busy(4). If you see telephony_provider_permission_denied, the SIP trunk credentials are not authenticated(4).
Next Steps
Check your origination setting in your SIP trunking provider and review the logs there(2). For urgent support, you can reach out via:
HI.
When I try to modify the Termination URI as you suggested:
I get an Internal Server Error.
Hello @falchetto.dev
Can you share the org id?
And for the screenshot, you need to not add the “sip:” as a prefix
Hi Omar.
What do you mean by Org ID?
I used sip: as a prefix, but the system returns an Internal Server Error.
Hello @falchetto.dev
I meant to not add it
And for the org id you can get it from settings → workspace
To find your workspace ID (also called org ID) in Retell AI, navigate to your workspace settings page.(1)
You can access your workspace settings in the system settings page, and retrieve the workspace ID there.(1)
Specifically, go to Settings → Workspace to locate your workspace ID/org ID.(2)(3)(4)
Org ID is org_YpPGMGLBt4ZubN4a
Hello @falchetto.dev
Are you able to see these calls on your call logs on your provider?
Based on the available sources, when calls aren’t appearing in your Retell AI call history, you should check your telephony provider’s call logs to see if the calls reached your system(1).
If calls are being dropped mid-transfer or experiencing connection issues, you should review your telephony provider settings and SIP configuration, as issues on the provider side can prevent calls from being properly logged(1).
For missing call logs, common causes include:
- Phone Number Format: Try searching with the E.164 format (including the +1 prefix)(1)
- Quick/Abandoned Calls: Missed or abandoned calls that hang up quickly sometimes don’t get logged in the agent’s call history(1)
- Call Logging Settings: Call logging may need to be enabled for quick/abandoned calls in your system settings(1)
If you’re still experiencing issues after checking these items, you can reach out through Discord(1).
Excuse me, but is there a Customer Service department?
I was invited to a Google Meet call by Oscar Ortega for Wednesday, February 11, from 6:30 p.m. to 6:45 p.m. I stayed on the line for about an hour and no one showed up.
Is there any way to resolve this issue or not?
In the meantime, I purchased a Twilio number: let’s see if I have better luck with this number at least…
Hello @falchetto.dev
Can you tell me how you booked this appointment?
I’m an AI assistant for Retell AI, and I don’t have access to specific user accounts or individual appointment booking histories. However, I can explain how appointment booking works with Retell AI.
Retell AI’s appointment booking system can be used in various scenarios such as a virtual front desk, sales and marketing, and operations for tasks like handling initial queries, directing calls, setting up consultations or demo appointments, and automated follow-ups(1).
The platform integrates with Cal.com to enable AI agents to book appointments directly. To set up appointment booking, you need to configure the Cal.com API Key and Event Type ID in your Retell AI agent(2)(3).
If you’re looking for details about a specific appointment booking, you would need to check your call logs or contact Retell AI support directly with your call ID or account information.
Is there something specific about appointment booking functionality in Retell AI that I can help you with?
