Fix an empty sender pool (`SENDER_POOL_EMPTY`)

SENDER_POOL_EMPTY is a deterministic, pre-send rejection: your request named a valid pool, Orbit looked up the pool, and found it has no members to draw a sender from. The send never reaches a provider, so nothing to retry — add a member to the pool (or route through a different pool) and send again.

Symptoms

The send request returns HTTP 422 with code SENDER_POOL_EMPTY, and the response names the pool that was empty.
The dashboard Delivery Log shows no row for the message — the send was rejected before queueing, so there is nothing to deliver.
The pool’s detail page prompts you to add a DID, and the senders list for the pool is empty.

An identical 422 also comes back from the pool preview endpoint (GET /api/v1/messaging/sender-pools/{id}/preview) when the pool has no members, so the symptom surfaces before you send real traffic if you preview first.

Causes

The pool row exists and resolves — the failure is membership:

The pool’s sender_dids list has no entries. Two ways a pool reaches that state: it never had members (created with an empty list and never filled, or the last member was removed), or the send carried a narrower recipient filter and none of the pool’s members were eligible, leaving zero candidates for that recipient.
A messaging service, campaign, or sender routing rule still points at the pool, so every send routed through it fails with the same code.

Fix: put a sender in the pool

Either fix the pool itself, or route the send elsewhere — tenant-owned controls only.

Add at least one member to the pool. A pool member can be an E.164 DID, a numeric short code, or an alphanumeric sender ID — update the pool with PATCH /api/v1/messaging/sender-pools/{id} and set sender_dids, or add the sender in the dashboard’s pool editor. Make sure the sender is one your organisation actually owns: GET /api/v1/numbers lists the DIDs on your organisation before you send.
Route through a pool that has members. Pass a different sender_pool_id on the request, or repoint the wiring that led here — a messaging service’s default pool, a campaign, or a routing rule — at a non-empty pool.
Retry the send. SENDER_POOL_EMPTY is rejected before any pick is made, so no selection state was written for the recipient — the retry routes cleanly, and the same idempotency key resubmits without a duplicate.

Distinguish it from the neighbouring codes

Code	HTTP	What fired	Fix
`SENDER_POOL_EMPTY`	422	The pool exists but has no members	Add a member to the pool, or route through another pool
`SENDER_POOL_NOT_FOUND`	404	The pool id names no pool at all — a wrong or deleted id	Verify the id, or re-create the pool
`NO_SENDER_CONFIGURED`	422	No pool was named, and your organisation has no sender anywhere — no default sender, no active phone number	Register a sender first

The telling difference: SENDER_POOL_EMPTY is pool-level state (a good pointer, an empty list), SENDER_POOL_NOT_FOUND is the pointer itself (there is no pool), and NO_SENDER_CONFIGURED is organisation-level state (no sender of any kind yet).

Example envelope

curl -X POST https://api.orbit.devotel.io/api/v1/messages/sms \
  -H "X-API-Key: dv_live_sk_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+14155550100",
    "sender_pool_id": "pool_emptypool",
    "body": "Order shipped"
  }'

returns HTTP 422:

{
  "error": {
    "code": "SENDER_POOL_EMPTY",
    "status": 422,
    "message": "Sender pool pool_emptypool has no DIDs configured"
  }
}

Sender pools — create pools, add members, and understand selection strategies.
Sender resolution — where the pool pick sits in the full precedence chain.
Troubleshoot sender resolution and pool errors — the three sibling codes (SENDER_REQUIRED, SENDER_POOL_NOT_FOUND, NO_SENDER_CONFIGURED).
FAQ: Why did my send return 422 SENDER_POOL_EMPTY? — the one-line version of this page.
Error codes — the full sender error table.

​Fix an empty sender pool (SENDER_POOL_EMPTY)

​Symptoms

​Causes

​Fix: put a sender in the pool

​Distinguish it from the neighbouring codes

​Example envelope

​Related references