DLR Recovery Week: Unknown Share Must Clear Before Volume Returns

Restoring full traffic volume after a freeze requires waiting for the share of unknown delivery reports to subside. Prematurely ramping up throughput on unstable routes leads to wasted balance and silent failures via your DLR webhook. Success depends on verifying that carriers are once again providing terminal handset states.

The mechanics of unknown DLR spikes during traffic recovery

When an SMS campaign experiences a freeze due to an unexpected surge in unknown delivery reports, resuming full volume immediately is a costly error. Unresolved unknown statuses signal that upstream carrier routes are dropping delivery receipts or failing to report final handset states. If you ramp up traffic based on optimism rather than clean telemetry, you risk burning balance on unverified delivery paths. To understand the initial trigger, review our guide on DLR incident week: unknown spike is a stop line. Recovery requires verifying that downstream carriers acknowledge terminal states before unlocking higher throughput.

Measuring true unknown share after a freeze

To determine whether a route is truly ready for restored volume, calculate the unknown share over tight 15-minute sampling windows rather than daily averages. A route is considered unstable if the proportion of unconfirmed delivery receipts remains above 5%. Continuing to push OTP or transactional messages through ambiguous paths causes silent delivery failures. If high unknown rates persist over time, your account risks falling into an DLR second month: unknown share that became a habit where reporting accuracy permanently degrades.

Clearing DLR telemetry: step-by-step audit

Before restoring traffic, trace webhooks and status callbacks across your account. Differentiate between unconfirmed network acknowledgments, expired validity windows, and hard carrier rejections by consulting the undelivered, rejected, expired. Execute a low-volume canary test using JIT number assignment to observe clean webhook responses. Only when the terminal status ratio returns to normal should automated volume limits be relaxed.

Table: DLR recovery metrics and traffic rules

Setting prepaid thresholds and platform guardrails

Financial controls protect your platform when testing unverified routes. Maintain a minimum USD 20 prepaid floor to keep live webhooks active and prevent billing interruptions during recovery phases. As volume returns and monthly spending approaches a soft review near USD 1,000/month, compliance monitoring ensures that route quality stays within acceptable bounds. Utilizing prepaid hold mechanisms guarantees that funds are allocated only when real-time routing checks pass successfully.

Start with IOSOR

Unknown share must clear on the recovered corridor before volume returns. Export the clear proof — unknown percent down, terminal statuses assigned, same correlation window. Do not ramp the next blast while unknown still sits. This week is a clear-gate, not the maintenance drain playbook and not a second-month habit hunt.

IOSOR takeaway

Recovery week returns volume only after unknown clears — not after the window ends.

Do: hold the ramp until the unknown share is gone on that corridor.

Don’t: resume blast while unknown still occupies the report, or call a drained queue a clear.