u/Educational-Fox6111

I've seen number of businesses lose clients or deals because emails silently landed in spam. A proposal that looked ignored. A follow-up that seemed rude not to answer. An invoice reminder that prompted a confused call from a client who said they never got it.

None of these had bounces or errors. The emails sent. They just didn't arrive where they were supposed to. The problem is almost always one of three things:

• Authentication not set up properly: SPF, DKIM, and DMARC tell email providers that your domain is legitimate. Without them configured correctly, providers treat your emails with more suspicion.
• Domain reputation: Gmail and Outlook score your domain over time based on engagement. A new domain, an old inactive list, or a spike in spam complaints can drop that score without any alert.
• Blacklist: your domain or IP can end up on a blacklist from something as simple as a previous email provider's behavior.

All three are invisible unless you check.

Customer retention was frustrating for me. Users signing up, not activating, churning fast. I assumed the problem was product-market fit. I Spent two months iterating on the product. Added features. Simplified the UI. Wrote better onboarding copy.

Finally set up Google Postmaster Tools, takes about 10 minutes and it's free. Domain reputation was at Medium. A significant chunk of my onboarding emails, trial nudges, and activation sequences were never reaching new users' primary inboxes.

Fixed the deliverability. Retention improved noticeably within a month on the same product, same copy, same sequences. The cheapest fix with the biggest impact. Should have been week one. What's the simplest thing that had an outsized impact on your metrics?