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Email Deliverability 4 min read October 16, 2026

Why B2B Sales Proposals Land in Spam: 5 DNS and Configuration Traps

Sending high-stakes proposals from an unauthenticated domain is one of the costliest mistakes in B2B sales. Avoid these 5 common domain configuration traps.

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OpsTrellis Engineering & QA Practice

Practical guides and technical notes prepared by the OpsTrellis engineering team covering Playwright automation, software QA, and email delivery protocols.

The Cost of Silence in B2B Deals

When a prospective client goes silent after asking for a proposal, sales teams assume they chose a competitor. In reality, up to 25% of B2B proposals land in the client’s spam or quarantine folder without either party realizing it.

Trap 1: Broken Return-Path (Envelope-From) Alignment

If your visible "From" address does not align with the technical return-path server address, SPF alignment fails under DMARC, triggering spam filters.

Trap 2: Shared Host IP Reputation Contamination

If you send email through basic shared hosting servers, other spammy accounts sharing that same IP can drag down your deliverability score. Using authenticated Google Workspace or Microsoft 365 solves this.

Trap 3: Missing Custom Tracking Domains

When using email tracking tools, generic tracking links are often blacklisted. Always configure a custom CNAME tracking domain (e.g. track.yourdomain.com).

Trap 4: Trigger Words & Heavy Attachments

Avoid sending proposals as heavy 20MB PDFs with spam-triggering phrases. Host proposals on clean web links or optimized PDFs under 2MB.

Practical Next Steps

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