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Error codes

phone_number_required

Caller number must be chosen. When phone_number_id is omitted, the agent's outbound number is used. This agent is assigned to several outbound numbers, so the API will not guess which one your contact should see.

What it means

The API returns HTTP 422 with error.code set to phone_number_required. The default message is: "This agent has more than one outbound number. Choose one with phone_number_id."

Common causes

• The agent is assigned to more than one outbound number.

How to identify it

Check the response status (422) and error.code (phone_number_required). Branch on error.code, not on the message text: messages can be reworded, codes do not change within v1. Log error.request_id (also sent as the X-Request-Id header) so support can find the request.

How to fix it

• Send phone_number_id, or assign the agent to a single outbound number in the console.

Retry guidance

Sending the request unchanged fails the same way. Fix the cause first (see How to fix it), then send it again.

Did anything happen?

This request was refused before any call was placed and before anything was charged.

Idempotency

Nothing was done and the refusal is not stored under the Idempotency-Key. Fix the cause, then send the same request (with the same key if you sent one).

Who can fix it

The developer who sends the request can fix it; no administrator action is normally needed.

When to contact support

If the error persists after the steps above, contact support@relationsai.com. See Support for what to include (the request_id, the time in UTC, the operation, and whether you used a test or live key) and what never to send (API keys, Authorization headers, webhook signing secrets, recording links, transcripts or customer data).

Example error response

JSON
{
  "error": {
    "code": "phone_number_required",
    "message": "This agent has more than one outbound number. Choose one with phone_number_id.",
    "details": {
      "agent_id": "agent_3hT9kQ2mVx7RbN4pLc8Wz1"
    },
    "request_id": "req_beny5osdfwrs6kgzv4uhhcav",
    "retry": "no",
    "doc_url": "https://docs.relationsai.com/errors/phone_number_required"
  }
}

Incorrect and corrected request

Incorrect: The agent has two outbound numbers and none was chosen.

Text
POST /v1/calls

{
  "agent_id": "agent_3hT9kQ2mVx7RbN4pLc8Wz1",
  "to": "+919000000001"
}

Corrected: Names the caller number with phone_number_id.

Text
POST /v1/calls

{
  "agent_id": "agent_3hT9kQ2mVx7RbN4pLc8Wz1",
  "to": "+919000000001",
  "phone_number_id": "pn_5Lq8Xc2Rk9TzW3mBv7Np4d"
}

Operations that can return this error

• POST /calls: Place a call
• POST /campaigns/{campaign_id}/start: Start a campaign

See all codes in the error-code reference.