If your business email is going to spam, the cause is usually not your wording. It is usually missing or broken settings on your domain (SPF, DKIM and DMARC), or a sending address that the big email providers have learnt not to trust. You can check both yourself in about ten minutes, and this guide shows you how.

Most people only find out when a client says, “I never got your invoice,” weeks after it was sent. The quotation you worked on all weekend may be sitting in a junk folder. Let’s find out why.

Why business email goes to spam: the short version

Gmail, Outlook and Yahoo receive huge amounts of fake email. To protect their users, they ask every message one question: can you prove you really come from the business you claim to be? If the answer is unclear, the message goes to junk or gets blocked.

The proof comes from three DNS records on your domain. You don’t need to understand the technical details, just what each one does:

Record	What it does, in plain English	What happens if it’s missing or wrong
SPF	A list of the servers allowed to send email for your domain.	Mail sent from a server that isn’t on the list looks forged.
DKIM	A digital signature on every email, showing that it came from you and wasn’t changed on the way.	The receiving server can’t confirm the message is genuine.
DMARC	Tells receivers what to do when SPF or DKIM fails, and sends you reports.	You have no visibility, and anyone can send email pretending to be you.

These records are no longer optional. Google’s email sender guidelines require everyone who sends to Gmail to set up SPF or DKIM, and anyone sending more than 5,000 messages a day needs SPF, DKIM and DMARC. Microsoft announced the same rule for high-volume senders to Outlook.com, Hotmail and Live addresses. Since 5 May 2025, mail from those senders that doesn’t comply is routed to the Junk folder. Microsoft also says it strongly recommends all senders set up all three, whatever their size.

A small business sending 50 emails a day is not a “bulk sender”. The point still stands: providers increasingly treat unauthenticated mail as suspicious.

Seven common reasons, and how to spot each one

1. You’re sending business mail from a free Gmail or Yahoo address

Writing to clients from yourbusiness2019@gmail.com doesn’t automatically send you to spam. It does make you look like every scammer who also uses a free address. You also can’t set up SPF, DKIM or DMARC for a domain you don’t own. Getting an address on your own domain (you@yourbusiness.com) is the foundation for everything below.

2. Your SPF record is missing, duplicated or out of date

A common story: a business moves from its hosting company’s email to Google Workspace or Microsoft 365, and nobody updates the SPF record. Another common one: two SPF records are added because two people each “fixed” it. A domain should have only one SPF record, listing every service that sends on your behalf: your mailbox provider, your invoicing software, your newsletter tool and your website.

3. DKIM was never switched on

With many email services, DKIM doesn’t work until someone generates a key and adds it to your DNS. Google’s own DKIM setup guide for Workspace admins walks through it. If nobody did this step when your email was set up, you are sending unsigned mail.

4. Your website’s contact form sends email that fails the checks

Many WordPress sites send form notifications and order receipts straight from the web server, using your domain’s name but not an authorised server. Those messages can fail SPF and DKIM and drag down your domain’s reputation. Sending them through your real email service or a proper sending service fixes it. If your site was ever hacked, it may also have sent spam in your name. Our post on the recent WordPress core security flaw explains how to keep a site patched.

5. Your server or domain is on a blocklist

On cheap shared hosting, your website and email may share a server with hundreds of other sites. If one of them sends spam, the server’s IP address can be blocklisted, and your mail suffers with it. A sudden drop in replies “all of a sudden” is often this.

6. People are marking your emails as spam

Google asks senders to keep the spam rate reported in its Postmaster Tools below 0.3%, and recommends staying below 0.1% (source). 0.1% is one complaint for every thousand emails. Bulk-mailing a contact list you bought, or people who never asked to hear from you, is the quickest way to cross that line. Marketing emails also need a clear, working unsubscribe link.

7. The message itself looks like spam

Content matters less than most people think, but it still counts. Watch for a single large image with almost no text, link shorteners, attachments with unusual file types, all-caps subject lines, and a “From” name that doesn’t match your business. Fix the settings first. Then keep emails plain, honest and personal.

How to check if your business email is going to spam

You don’t need special software to start. Do these four checks in order:

1. Send a test to yourself. Send a normal email from your business address to a personal Gmail account and to an Outlook.com account. Did it land in the inbox, the Promotions tab or Junk?
2. Read the verdict in Gmail. In Gmail on a computer, open the message, click the three dots next to Reply, and choose Show original (Google’s steps). Near the top you’ll see lines for SPF, DKIM and DMARC. You want PASS on all three (here’s what a passing result looks like). “FAIL”, “SOFTFAIL” or “NONE” tells you exactly which record needs work.
3. Look for the warning signs on mobile. In the Gmail app, open the message and tap View details. Google says an authenticated message shows a “Mailed by” and a “Signed by” line with your domain, and that a question mark next to the sender’s name means it isn’t authenticated. If your clients see that question mark beside your name, it’s not a good look.
4. Analyse the headers. Copy the full original message and paste it into Google’s free Admin Toolbox Messageheader tool. It turns the raw header into something easier to read.

If all three checks pass and you still land in spam, the problem is more likely reputation (a blocklist or complaints) or content. That needs a closer look at your sending history.

What to fix first

• Move to your own domain if you are still on a free address.
• Publish one correct SPF record that lists every service that sends for you.
• Turn on DKIM in your email provider and add the key to your DNS.
• Add a DMARC record starting at p=none, so you get reports without blocking anything. Tighten it once the reports show everything passes.
• Route website emails through an authorised service, not the bare web server.
• Clean your mailing list and stop emailing people who never opted in.

Change one thing at a time and test again after each change. DNS updates can take a few hours to spread.

Frequently asked questions

Why are my emails going to spam all of a sudden?

A sudden change usually means something changed behind the scenes. Someone may have edited your DNS while moving hosting, your server’s IP may have been blocklisted, or your website may have started sending mail it shouldn’t. Run the “Show original” check above to see which of SPF, DKIM or DMARC has started failing.

Does Google Workspace or Microsoft 365 stop my emails going to spam on its own?

A good provider helps, but you still have to add the right SPF, DKIM and DMARC records to your own domain. If those records are missing or wrong, even paid email can land in junk.

Is DMARC compulsory for a small business?

Google and Microsoft only make it a requirement for senders above 5,000 emails a day. Both recommend it for everyone, and it protects your clients from emails pretending to come from you.

Can I fix this myself?

Yes, if you are comfortable editing DNS records at your domain registrar. One typing mistake can stop all your email, so take a note of the existing records before you change anything.

Want someone to just fix it?

Setting up business email and deliverability is part of our Tech Concierge service. We set up email on your own domain with Google Workspace or Microsoft 365, configure SPF, DKIM and DMARC properly, and track down why your emails are landing in spam. You can do everything above yourself. If you’d rather spend the time running your business, book a free 15-minute call and tell us what’s happening with your email.