> ## Documentation Index
> Fetch the complete documentation index at: https://docs.orbit.devotel.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Troubleshooting hub
> Every troubleshooting page in one place — a sectioned index of all runbook pages under the Reference group.
# Troubleshooting hub
The Reference group in the sidebar is a flat list of well past 60 pages, and
most of them are runbooks. This page exists so you never have to scan that
list: every troubleshooting page lives in one of the sections below, grouped
by the surface it works on.
The Reference index itself — error codes, webhook events, glossary, and FAQ —
lives at the top of the sidebar group; this hub indexes only the runbook
pages.
One link basename changed shape over time: the
[message stuck in queued](/reference/troubleshooting) page answers to the
`reference/troubleshooting` route because it was the first runbook. Every
other runbook lives under `/troubleshooting/`.
Diagnose a message stuck in the pre-send queue, one accepted by the provider
that never reports a delivery outcome, and the recovery pattern when the
carrier receipt itself goes missing.
* [Message stuck in queued](/reference/troubleshooting) — a message that
cannot get out of the pre-delivery stage.
* [Message sent but no delivery receipt](/troubleshooting/submitted-no-receipt) —
the row reached `sent` but a `delivered`/`undelivered` outcome never lands.
* [Recover a failed or late DLR](/troubleshooting/failed-dlr-recovery) —
retry and backfill a missing delivery receipt.
* [Message undelivered or failed](/troubleshooting/message-undelivered-failed) —
a terminal non-delivered outcome and what to do next.
Buy numbers, get sender IDs approved, work warming caps, and handle India DLT
or 10DLC gates.
* [Number purchase failure](/troubleshooting/numbers-provisioning-failed) —
inventory races and provisioning retries.
* [Number warming caps](/troubleshooting/number-warming-caps) —
`DAILY_CAP_EXCEEDED`, `WARMING_QUOTA_EXCEEDED`, and `NUMBER_MPS_EXCEEDED`.
* [Sender ID rejected before send](/troubleshooting/sender-id-not-registered) —
the pre-send `SENDER_ID_NOT_REGISTERED`/`SENDER_ID_NOT_APPROVED` gate.
* [Sender-ID registration rejected or expired](/troubleshooting/sender-id-registration-resubmit) —
resubmit or reactivate a declined sender.
* [India DLT gate](/troubleshooting/in-dlt-gates) — a 422 with a
`dlt_template_id`/`dlt_entity_id` requirement.
* [10DLC campaign rejected](/troubleshooting/10dlc-campaign-rejection) —
resubmit a campaign the carrier declined.
Triage SIP trunk health, call quality, blocked destinations, and TCPA dialing
windows.
* [SIP trunk](/troubleshooting/sip-trunk) — registration, health, failover,
and capacity.
* [Voice call quality](/troubleshooting/voice-call-quality) — one-way audio,
dead air, jitter, and PDD.
* [TCPA blocked calls](/troubleshooting/tcpa-window-blocked-calls) — the
dialing window a blocked call fell outside.
* [Suspect voice destination](/troubleshooting/voice-destination-blocks) —
destination and emergency blocks.
* [Failover and failback](/troubleshooting/media-planes-failover-or-failback) —
a call that fails right after a regional move.
DNC, consent receipts, destination blocks, and the strict-sender-id FQDN
gate.
* [DNC pre-flight returns 403](/troubleshooting/dnc-check-gated) —
`DNC_SYNC_NOT_ENABLED` on a send gate.
* [CONSENT\_RECEIPT\_INVALID](/troubleshooting/consent-receipt-invalid) — a
caller receipt the API cannot verify.
* [SMS destination blocks](/troubleshooting/sms-destination-blocks) — the
spending and destination gate for SMS.
* [Strict sender-ID FQDN gate](/troubleshooting/strict-sender-id-invalid-destination) —
`SENDER_INVALID_FOR_DESTINATION` when strict mode rejects a custom sender.
Delivery retries, DLQ and replay, endpoint creation errors, and duplicate
events.
* [Failed webhook deliveries](/troubleshooting/webhook-deliveries) —
retries, DLQ, and replay.
* [Webhook endpoint creation errors](/troubleshooting/webhook-endpoint-creation) —
shape and permission errors when registering an endpoint.
* [Duplicate webhook events](/troubleshooting/webhook-event-dedup) —
consumer-side dedup of repeated deliveries.
OTP sends and checks, plus the TOTP/push/passkey/backup-code factor suite.
* [Verify OTP](/troubleshooting/verify-otp) — a send or a check that fails.
* [Verify factor suite](/troubleshooting/verify-factor-suite) — TOTP, push,
passkey, and backup codes.
Warmup, bounces and complaints, DNS verification drift, and inbound routing.
* [Email bounces and complaints](/troubleshooting/email-bounces-complaints) —
reputation and suppression follow-ups.
* [Email DNS drift](/troubleshooting/email-dns-drift) — verification drift
and recovery.
* [Inbound email never routes](/guides/inbound-email-troubleshooting) — parse
domain match rules and trigger issues.
Spend caps, insufficient balance, and billing-pause blocks on outbound.
* [Spend-cap refusals](/troubleshooting/spend-caps-hit) — daily caps per
channel.
* [INSUFFICIENT\_BALANCE](/troubleshooting/insufficient-balance) — the 402
that blocks a send when credits cannot cover it.
* [Billing-gate outbound blocks](/troubleshooting/billing-pause-block-recovery) —
recovery from the pause block.
Auth and IP allowlists, schema readiness, rate limits, and import/flow
failures.
* [Authentication and IP allowlist](/troubleshooting/auth-and-api-keys) —
key mode and IP-allowlist failures.
* [Tenant schema incomplete](/troubleshooting/tenant-schema-incomplete-503) —
the 503 that gates a route while the schema finishes.
* [Rate limits and cool-downs](/troubleshooting/rate-limits) — 429 cooldown
recovery.
* [Import jobs](/troubleshooting/import-jobs) — an import that fails or
stalls.
* [Flow executions failed](/troubleshooting/flow-executions-failed) — a flow
whose execution returned an error.
Inbound SMS/RCS/WhatsApp route misses, RCS undelivered, and Telegram.
* [Inbound SMS no route](/troubleshooting/inbound-sms-no-route) — inbound
to your number never arrives.
* [Inbound WhatsApp or RCS no route](/troubleshooting/inbound-channels-no-route) —
an inbound message with no route assignment.
* [RCS undelivered](/troubleshooting/rcs-undelivered) — a message that never
reached an RCS-capable device.
* [Telegram channel errors](/troubleshooting/telegram-connect) — connect,
push, and mutual-hand-off errors.
Remaining runbooks for agent queues, conversations, co-browse, and quarantine.
* [Agent eval-queue failures](/troubleshooting/agent-eval-queue) — an eval
that stalls or fails to start.
* [Conversation merge refused](/troubleshooting/conversation-merge) —
`WEAK_IDENTITY_MATCH_REQUIRES_CONFIRMATION`.
* [Co-browse stuck](/troubleshooting/cobrowse-stuck) — a session that never
hands off.
* [Suspicious or empty queue](/troubleshooting/enqueued-empty-states) — an
order or import stuck in an enqueued state.
* [Quarantined media file](/troubleshooting/file-scan-quarantined) — the
`FILE_SCAN_QUARANTINED` outcome.
* [DSAR export retry](/troubleshooting/dsar-export-failures) — requeue when
a data-subject export fails.
## Where error codes fit in
When the failure is a specific `code` on the API envelope, match that code
against the [Error Code Reference](/reference/error-codes) first; pick the
runbook from the section above once you know the surface.
## How to use a runbook
Every page follows the same shape — a cause table that maps symptoms to
fixes, a full-error sample you can paste in a ticket, a decision checklist,
the fixes you should NOT try, and when to escalate. Anything in this list
matches that pattern; pick one, do not freestyle.
For a failure that does not map to one of the runbooks, open a ticket with
the steps you tried, the `code` from the API envelope when present, and the
output of the endpoint you hit.