A customer calls asking why you never replied to their enquiry. You did - two days ago. Your reply is sitting in their spam folder, next to your invoice from last week and your quotation from the week before. Every one of those is money leaking out of your business.
The good news: emails going to spam is almost never a mystery. Mailbox providers like Gmail and Outlook score every message on a short list of factors, and most businesses fail two or three of them. Here they are, in the order you should check.
In plain language: anyone on the internet can send an email claiming to be from yourdomain.com. Three DNS records exist to prove which mail is really yours.
SPF is a public list of servers allowed to send email for your domain. DKIM is a tamper-proof signature stamped on each message. DMARC tells receivers what to do with mail that fails the first two - and since 2024, Gmail and Yahoo effectively require all three for anyone sending in volume.
Check yourself in two minutes: use a free tool like MXToolbox or send a message to a Gmail account and hit "Show original" - you want SPF, DKIM, and DMARC all showing PASS. If any fail, the records live in your domain's DNS settings, and your email provider (Google Workspace, Microsoft 365, Zoho) publishes copy-paste values. Start DMARC with a monitoring-only policy (p=none) so nothing legitimate gets blocked while you verify.
One trap: every tool that sends email for you - your newsletter platform, CRM, invoicing app - needs to be included in SPF and have its own DKIM set up. The forgotten invoicing tool is a classic silent failure.
Filters read your emails the way a suspicious human would. Red flags: ALL CAPS subject lines, too many exclamation marks, one giant image with almost no text, link-shortener URLs, and attachments on cold emails.
Subtler ones: a mismatch between the link text and where it actually points, and sending from a no-reply address.
The fix is to write like a person. Plain, mostly-text emails with one clear link consistently outperform image-heavy blasts - both in deliverability and replies. Keep a genuine reply-to address; replies are a strong positive signal to Gmail.
Deliverability is a reputation game, and your list is your reputation. Every bounce, every spam complaint, every ignored email lowers your score with mailbox providers.
The three list sins: emailing old addresses that now bounce, emailing people who never asked to hear from you, and continuing to email people who have not opened anything in a year.
The cleanup: remove hard bounces immediately (good platforms do this automatically), never buy or scrape lists, and run a re-engagement pass on anyone inactive for six months or more - one honest "still want these?" email, then remove the silent ones. A smaller list that opens your mail will land in more inboxes than a big list that ignores it.
On cheap shared hosting, your website's contact form and notification emails often go out from the same IP address as hundreds of other websites - including, sometimes, actual spammers. Their behaviour drags down your reputation.
Check your sending IP on a blacklist checker (MXToolbox again). If your host's IP is listed, the fix is not to fight the blacklist - it is to stop sending important mail through shared hosting at all.
Route transactional mail (form notifications, invoices, password resets) through a proper email service - Google Workspace, or an SMTP relay like Amazon SES, Brevo, or Postmark. This is standard plumbing in the automation systems we build: business-critical email never rides on shared hosting.
A new domain, or a quiet domain, that suddenly sends 2,000 emails in an hour looks exactly like a spammer waking up. Providers throttle or junk the lot.
Warm up instead: start with small daily volumes to your most engaged contacts and roughly double every few days over two to four weeks. Keep daily volume consistent afterwards - spiky senders get penalised.
Everything above is DIY-able in an afternoon if you are comfortable editing DNS records: authenticate the domain, clean the list, move transactional mail off shared hosting. Do the SPF/DKIM/DMARC check today - it is the highest-leverage twenty minutes in email.
It stops being DIY when the pieces interact: multiple sending tools, a domain reputation already damaged, DMARC reports nobody can read, and revenue-critical invoices and quotes bouncing while you troubleshoot. Deliverability recovery done wrong - like jumping straight to a strict DMARC policy - can block your own legitimate mail.
If chasing spam folders is eating your team's week, talk to Kentaurx - we build systems that make this problem disappear.
Send a test to a Gmail address you control and check the spam folder, then open "Show original" to see SPF, DKIM, and DMARC results. Free tools like Google Postmaster Tools and MXToolbox show your domain reputation and blacklist status.
SPF is a public list of servers allowed to send mail for your domain. DKIM is a digital signature proving a message wasn't altered. DMARC tells receiving servers what to do when the first two fail. Together they prove your email really came from you.
It removes the biggest technical strike against you, and improvement often shows within days. But if your domain reputation is already damaged by bounces or complaints, expect two to four weeks of clean, consistent sending before inbox placement recovers.
Shared hosting usually sends them from a low-reputation IP shared with hundreds of other sites, often without proper authentication. Route form and notification emails through an authenticated SMTP service like Google Workspace, Amazon SES, or Brevo instead.
Whatsapp: +91 93618 97364
Email: We@kentaurx.com
