7 deadly sins of email deliverability - pt. 1

Hey there,

Kevin here from Astris Partners.

I need to share something terrifying: over 90% of B2B companies we speak with are making critical deliverability mistakes that could blacklist their main domain forever.

They think their emails are reaching prospects, but they're actually poisoning their business reputation with every send.

Just one wrong move can mean every email to paying customers, team members, and partners vanishes into spam jail. You're not just losing deals - you're killing your entire business communication.

Deadly Sin #1: Using Your Main Domain for Cold Email

Your main domain handles everything: website, employee emails, client communication, invoices, contracts. When you send cold emails from this domain, you're putting your entire business communication at risk.

Cold email is unsolicited by definition. Even with perfect messaging, some people will mark it as spam. When those complaints pile up against your main domain, email providers start treating ALL emails from your domain as junk.

Suddenly your proposal to your biggest client ends up in spam. Your team's internal communication gets blocked. Your customer support emails disappear.

The fix: Always use secondary domains for cold outreach.

If your main domain is companyname.com, buy variations like getcompanyname.com or trycompanyname.com or companynameHQ.com.

Set up dedicated mailboxes on these domains exclusively for cold email. This creates a firewall protecting your primary business communication no matter what happens with outreach.

Deadly Sin #2: Missing Email Authentication

SPF, DKIM, and DMARC records are essential for email trust. Without these properly configured, receiving servers don't trust your emails. Your messages look suspicious before anyone reads the content.

What each one does:

• SPF: Tells receiving servers which IPs can send emails for your domain

• DKIM: Adds digital signature proving your email wasn't tampered with

• DMARC: Tells servers what to do if your email fails the other checks

The fix: When setting up secondary domains, use dedicated platforms like Instantly or Smartlead that handle authentication automatically. If doing it yourself, properly configure SPF, DKIM, and DMARC records. This isn't optional - it's required for serious deliverability.

Deadly Sin #3: Sending Emails from Brand New Domains

Buying a domain today and sending cold emails tomorrow is a mistake. Email providers examine domain age, sending history, and engagement patterns. A brand new domain with no history suddenly sending emails looks suspicious, even with perfect authentication.

The fix: Warm up domains for at least 2-4 weeks before sending cold emails.

During warm-up, your mailboxes send and receive emails with other warmed mailboxes, gradually building reputation. Keep warm-up running even after you start cold outreach.

Pro tip: If you have old domains sitting unused, set up mailboxes on those. Aged domains are gold for deliverability.

Deadly Sin #4: Spray and Pray Messaging

Having no strategy and blasting the same generic message to everyone isn't just ineffective in 2025 - it's a guaranteed path to the spam folder.

Email service providers have sophisticated algorithms that detect when you're sending identical messages to massive lists. Within 50-100 emails, their systems recognize the pattern and start blocking the rest.

You think you sent 5,000 emails, but 4,500+ never had a chance to be seen.

Modern AI analyzes whether your message is relevant to the recipient. If you're sending identical messages to a CFO, head of sales, and marketing manager, the system realizes none of these roles would naturally receive the same outreach. Red flag.

The fix: Stop spraying, start strategizing.

Use spin syntax to create variations, but more importantly, create role-specific messaging. Your message to a CFO should focus on ROI and cost savings. Your message to a head of sales should emphasize revenue growth.

Relevance isn't just about personalization - it's about survival.

The Stakes Are Higher Than You Think

When we fix these issues for clients, we consistently see 5%+ reply rates compared to the industry standard of 0.7%. Some campaigns reach 30%+ reply rates.

One client went from blacklisted domains to generating a $250K deal from a single lead within 90 days of implementing these fixes.

The difference between success and failure in cold email often comes down to these technical fundamentals, not clever copywriting.

Next week, I'll cover the final three deadly sins that are killing your deliverability: spam triggers, design elements, and robotic sending patterns.

Rooting for your cold email success,

Kevin

P.S. If you're making any of these mistakes and want help fixing your deliverability before it's too late, book a free strategy call with me.