MailSequence
Log in Start with a paid plan

Campaign intervention guide

When to pause a cold-email campaign and what to fix before restart.

Pause immediately when identity, consent, suppression, or sender eligibility is compromised. Reduce volume when providers defer mail or health deteriorates. Investigate weak commercial results without confusing them with delivery failure.

Reviewed September 8, 2026 9 minute read Product behavior checked against current implementation
A pause protects sending while you investigate. Use the evidence to choose the scope: contact, inbox, domain, campaign, or workspace.

Pause immediately

SignalPause scopeRequired action
SPF, DKIM, or DMARC starts failingAffected inboxes or domainRepair and validate authentication on real test messages
Mailbox disconnects or loses sending readinessAffected inboxReconnect, retest SMTP, and confirm reply synchronization
Suppression or opt-out is not being honoredAffected campaign or workspaceStop sends, preserve evidence, repair the suppression path, and audit recipients
Provider restriction or persistent permanent failure patternAffected inbox or domainRead the full response, stop retries, and resolve the stated cause
Complaint rate approaches a provider boundaryAffected stream or domainStop the source audience and correct targeting, identity, and opt-out handling

For Gmail recipients, Google advises keeping reported spam below 0.1% and avoiding 0.3% or higher. Treat 0.3% as a hard ceiling and act earlier.

Reduce volume or hold new enrollment

Temporary deferrals, throttling responses, rising soft failures, a sudden reputation decline, or a sharp change in volume call for a controlled reduction. Google specifically advises reducing sending when messages begin bouncing or being deferred, then increasing slowly only after SMTP errors fall.

A persistent transient failure begins with a 4.x enhanced status class; a permanent failure begins with 5.x. The detailed response still matters. Do not blindly retry every 4.x result or treat every 5.x result as the same root cause.

When to suppress one contact

A hard bounce, unsubscribe, complaint, manual suppression, or clear stop request should make that recipient ineligible. One contact-level event may be isolated. A pattern across a source, segment, inbox, or domain calls for a wider investigation and pause.

Investigate commercial performance separately

Low replies, weak positive-reply rate, or poor conversion can indicate an audience, offer, timing, or copy problem. They deserve review, but they do not by themselves prove spam placement. Open-rate movement is especially unreliable and should not be used as a pause trigger.

Restart criteria

  1. Identify the affected contact, inbox, domain, campaign, and provider. Check the scope before expanding the pause.
  2. Preserve SMTP responses, authentication results, bounce categories, complaint evidence, and the recent change history.
  3. Fix the root cause and verify it independently with a controlled test.
  4. Confirm suppressions remain in force and no failed audience is automatically re-enrolled.
  5. Restart below the previous volume through one healthy, send-ready path.
  6. Hold the lower level while monitoring provider responses and health before expanding.

How MailSequence scopes intervention

MailSequence can suppress individual contacts, remove disconnected or SMTP-unready inboxes from eligibility, enforce shared domain capacity, cool down warmup, and pause a campaign when no eligible sender remains. Operators can then review inbox, domain, campaign, and bounce evidence before resuming.

Automated controls respond to configured and observed signals. They do not replace operator judgment about audience suitability, message relevance, provider policy, or applicable law.

Primary sources

Pause narrowly, fix the cause, and restart cautiously.

Use MailSequence controls to protect contacts, inboxes, domains, and campaigns without masking the evidence.

Start with a paid planExplore deliverability controls