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This guide shows how to integrate Retell AI with Vobiz using the dashboard so your AI agents can make outbound calls to any phone number.
Prefer using API/CLI? Check out the API setup guide for curl commands and programmatic integration.

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What you’ll build

A no-code outbound calling setup where your Retell AI agent reaches customers using your Vobiz phone number and SIP trunk for transport.

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Prerequisites

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Step-by-step setup

1

Open the phone numbers section

Log in to the Retell Dashboard, navigate to Phone Numbers in the sidebar, and click the + button to add a new number.
2

Select SIP trunking

Choose Connect to your number via SIP trunking. This lets you use your own Vobiz phone number and SIP infrastructure instead of buying a number from Retell.
3

Configure the SIP trunk

Fill in the required fields:
FieldValue
Phone NumberYour Vobiz number in E.164 format (for example, +1234567890)
Termination URIYour Vobiz SIP domain (for example, abc123.sip.vobiz.ai) - do not include the sip: prefix
SIP Trunk User NameYour Vobiz trunk username
SIP Trunk PasswordYour Vobiz trunk password
NicknameFriendly name (for example, Vobiz Main Line)
Click Save to complete the configuration.
4

Make a batch call

Click on your configured phone number and select Create a batch call. Fill in:
  • Batch Call Name - campaign name (for example, Customer Outreach)
  • From number - your configured Vobiz number
  • Upload Recipients - CSV file with phone numbers
  • When to send - Send Now or Schedule
Click Send or Schedule to launch the campaign.
Dashboard setup complete! Your Retell AI agent can now make outbound calls through Vobiz SIP infrastructure.

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Where to find your Vobiz credentials

For CSV format requirements, see the Retell batch calling docs.

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Troubleshooting

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”Phone number not found”

Phone number not configured in Retell.
  • Verify the number is in E.164 format (+countrycode + number).
  • Re-configure the phone number using the steps above.
  • Check that the number exists in the Vobiz Console.

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Call fails immediately

SIP authentication or configuration issue.
  • Verify your Vobiz username and password in the Vobiz Console.
  • Use the exact Vobiz domain (for example, abc123.sip.vobiz.ai).
  • Do not include a sip: prefix.
  • Try a different transport type (TCP vs UDP) in the trunk config.

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Agent doesn’t speak

Agent not configured or not published.
  • Ensure the agent is published in Retell Dashboard → Agents.
  • Check the agent has a voice configured.
  • Verify the agent ID matches the phone number config.
Need more detail? See the API troubleshooting guide for additional error scenarios.

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Next steps

  • Customize your agent - configure voice, personality, and prompts in Retell Dashboard → Agents.
  • View call analytics - monitor call logs and transcripts in Retell Dashboard → Calls.
  • Automate with API - trigger calls programmatically using the Retell AI API setup guide.
  • Monitor usage - track your Vobiz balance and call records.