Client Overview

A US-based HR technology platform helping enterprises automate recruitment workflows approached YellowInk Digital to fix their outbound email challenges. The client relied heavily on cold email outreach for pipeline generation but faced severe email reputation issues.

The Challenge

The client’s outreach campaigns were breaking down due to poor sender reputation and aggressive campaign practices:

• Open rates dropped below 10%
• Spam flagging rate spiked above 2%
• IPs were getting blacklisted
• Complaint rate escalated
• No email warm-up or domain segmentation in place

They were losing valuable leads, and their SDR team couldn’t trust the platform to deliver reliably.

The Strategy

We deployed a deliverability-first cold outreach rebuild with the following 4-layer plan:

IP Rotation & Infrastructure Cleanup

• Configured custom tracking domains and dedicated sending addresses
• Rotated between multiple email inboxes and subdomains to diversify risk

Warm-Up Protocol Setup

• Used Instantly’s built-in warm-up features and connected inbox sync
• Gradually scaled send volume to simulate organic engagement

List Hygiene & Segmentation

• Cleaned contact lists to remove low-quality emails and spam traps
• Segmented into high, medium, and unknown quality contacts

Deliverability Monitoring & Testing

• Ran inbox placement tests using Mail-Tester and GlockApps
• Set up Google Postmaster Tools to track domain reputation over time

Tools Used

Instantly · Mail-Tester · IPWarmup Tools · Google Postmaster · GlockApps · MXToolbox

Results Achieved

Within just 30 days of implementation, our optimizations led to significant gains across all key email performance metrics:

• Open Rate improved from 9.2% to 22.3%, reflecting stronger subject line testing, better targeting, and improved domain reputation.

• Spam Complaint Rate dropped from 2.1% to less than 0.2%, thanks to refined list hygiene, opt-in practices, and engaging content strategies.

• Bounce Rate decreased from 11.4% to 3.7%, driven by aggressive list cleaning and real-time email verification processes.

• Warm-Up Inbox Score surged from 57/100 to 94/100, indicating a significantly healthier sender reputation and inbox placement potential.

These results illustrate the impact of strategic email warm-up, sender reputation repair, and content personalization efforts.