"Error starting call" when running browser test call

Support Help
1

Hi, I’m having an issue starting a browser test call from my Retell AI agent.

Whenever I click “Run Test”, I immediately receive:

Error starting call

The agent is published, my browser microphone permission is enabled, and my account still has free-trial credit available.

I also tested different supported LLM models, but the same error occurs.

The agent-level webhook test is working successfully, so the webhook itself appears reachable.

No call/session appears in Call History after the failed attempt.

Could you please check whether there is an account, workspace, agent, or trial restriction preventing browser test calls from starting?

Thank you.

2

Hey @mussab

Since no call/session appears even in Call History, the failure is likely happening before the call registers — commonly caused by browser permission/domain issues or an LLM/agent configuration problem.

A few things to check :

  1. Custom LLM issues: If using a custom LLM, error_llm_websocket_open occurs when the websocket can’t open — check your LLM server is reachable. See custom LLM troubleshooting.

  2. Payment/trial restriction: no_valid_payment is a known error reason when no valid payment is on file (though you mention trial credit remains) — worth double-checking billing status.

  3. Public key domain allowlist: For web calls, Make a web call FAQ notes calls can fail before starting if the public key’s allowed domains, agent ID, or mic permission aren’t correctly set — worth re-verifying the allowed domain for your test.

  4. No call in history: This matches errors that occur before the session registers (e.g. error_user_not_joined, or an immediate rejection before call creation), rather than a mid-call disconnect.

Since the error is generic (“Error starting call”) with no call record, this needs a closer look at your specific agent config — check the browser console for the detailed error onError payload as noted in Make a web call,

since that reveals the actual failure reason (domain mismatch, invalid agent ID, etc.).

Best Regards.