Back to Case Studies
Healthcare / B2B · United States Deliverability Audit

20+ Sending Domains, 500k Monthly Volume — Bot Clicks and Spam Filters Killing Every Campaign

Bernard was running healthcare outreach at 500,000 emails per month across 20+ sending domains. Security scanners were pre-clicking every tracked link, corrupting all engagement analytics. Spam filters were actively blocking healthcare outreach before reaching any inbox.

20+
Sending domains fully audited and rebuilt
500k
Monthly volume stabilised without domain loss
4-6w
Full stabilisation timeline
0
Bot click false positives after link structure fix
The Situation

What Was Happening

Bernard's outbound operation ran healthcare campaigns at significant scale across 20+ sending domains. Two distinct problems were occurring simultaneously. First, enterprise security scanners at healthcare organisations were pre-clicking every tracked link in every email before the recipient saw the message — destroying all click analytics and causing false positive engagement signals. Second, spam filters were actively blocking healthcare-related outreach content before reaching primary inboxes. Both problems were happening across all 20+ domains with no clear prioritisation of which domains to fix first.

The Diagnosis

Root Cause

The Problem

Multiple domains with reputation damage from inconsistent send volume across the estate. Some domains were carrying far more than safe daily limits while others were underused. Link tracking patterns were triggering enterprise security proxies specific to healthcare organisations. Content patterns in the email body were flagged by spam filters. No structured domain health monitoring was in place, so damaged domains were continuing to send without detection.

The Fix

Full audit across all 20+ domains in priority order by reputation damage level. Blacklist clearance for any listed domains. DNS authentication rebuilt where broken. Sending volume redistributed across domains based on health score. Content and link structure reworked to avoid security scanner triggers. Domain health monitoring set up to catch future degradation before it becomes visible in campaign metrics.

The Work

What Was Built

01
Domain Inventory and Health Audit

All 20+ sending domains pulled and audited simultaneously. DNS records, blacklist status, sender score, and domain age checked for each. Reputation damage ranked by severity.

02
Blacklist Clearance

Domains listed on major blocklists identified. Removal requests submitted. Re-test scheduled post-removal to confirm clearance before returning to active rotation.

03
DNS Authentication Rebuild

Broken SPF records, mismatched DKIM selectors, and missing DMARC policies fixed across all affected domains in priority order.

04
Volume Redistribution

Sending volume rebalanced across the domain estate based on health score. High-damage domains pulled from rotation or put on controlled warmup ramp. Low-damage domains carrying more load temporarily.

05
Link Structure Rework

Tracked link format revised to reduce security proxy pre-click rates. Redirect chain simplified. Image tracking replaced with plain-text approach where possible.

06
Content Pattern Review

Email body content reviewed against known healthcare spam filter triggers. Flagged phrases and formatting patterns adjusted. Test sends run through Mail-Tester before campaign reactivation.

07
Monitoring Setup

Automated domain health monitoring configured. Weekly blacklist check and sender score review. Alert threshold set to flag any domain approaching reputation risk before it becomes a deliverability issue.

Tools Used

Tech Stack

MXToolboxGlockAppsSpamhausBarracudaMail-TesterCloudflareMicrosoft 365
The Result

Outcome

All 20+ domains audited and assigned to repair or maintain status. Sending volume of 500,000 per month stabilised across the full domain estate within 4 to 6 weeks. Bot click false positives eliminated after link structure rework. Domain health monitoring in place to prevent repeat incidents without manual oversight.

500k monthly volume stabilised across 20+ domains. Bot click issue resolved. Monitoring live.

Facing a similar problem?

30 minutes. No pitch. Walk away with a specific diagnosis and fix plan for your setup.

Book Free Audit Next Case: GoHighLevel Behavioral Pipeline