How to check if your business emails are going to spam

Why check, and how often?

Most owners find out about a spam problem secondhand: a customer says they never got the estimate, or an invoice sits unpaid because it landed in junk. By then it may have been happening for months. A deliverability check takes about half an hour, and you should run it once now, again after any change to your email host, CRM or website, and quarterly after that.

The check has two parts. A seed test shows you where mail lands today. The authentication check tells you why. If you want background on the records involved, read our SPF, DKIM and DMARC guide first. If you send marketing email in volume, also read our summary of Gmail and Yahoo sender requirements.

What you'll need

• Free test inboxes at Gmail, Outlook.com and Yahoo that you control and haven't used to email your business before (so past replies don't skew the results).
• Login access to every system that sends mail as your domain.
• Access to your domain's DNS settings, in case you need to fix records.
• A spreadsheet or notes page to record results.

Step 1: Run a seed test from every sender

List every place that sends email with your domain in the From address. For a typical service company that's:

• your regular mailbox (Google Workspace, Microsoft 365 or similar);
• your CRM or field service software (estimates, appointment reminders, invoices);
• your email marketing tool, if you use one;
• your website's contact or quote form notifications;
• your accounting or payment tool's receipts.

1. From each one, send a normal message to all three test inboxes. Use real content: an actual estimate template, a real reminder, a real newsletter. A one-word test message tells you little.
2. Wait a few minutes, then check each inbox, its spam or junk folder, and in Gmail the Promotions and Updates tabs.
3. Record where each one landed. Promotions isn't spam, but an invoice landing in Promotions is worth fixing.

Step 2: Read the authentication results in Gmail

1. Open one of the test messages in Gmail on a computer.
2. Next to Reply, open the More menu and choose Show original.
3. Near the top of the page that opens, find the lines for SPF, DKIM and DMARC. Each should say PASS.
4. Look at the domain named on the DKIM line. It should be your domain, not only your CRM vendor's domain. If it's the vendor's, DMARC may still fail even though DKIM technically passed, because the signing domain doesn't match your From address.
5. Repeat for a message from each system you tested.

Step 3: Check your DNS records directly

Google's free Admin Toolbox has a Check MX tool that looks up a domain's MX and SPF records and flags problems. Enter your domain and read the results. The most common finding on small business domains is two separate SPF records, usually because a CRM's setup instructions said to add a new one. A domain may only have one. Merge them into a single record.

Our free email domain check looks up your MX, SPF and DMARC records and the common DKIM selectors, then counts the DNS lookups inside your SPF record. Neither tool can see whether your CRM or invoicing tool signs with your domain, so keep the seed test from step 1.

Step 4: Set up Google Postmaster Tools

Postmaster Tools is Google's free dashboard for senders. It shows data about mail sent to personal Gmail accounts only, not Workspace business inboxes.

1. Sign in to Postmaster Tools with a Google account.
2. Add the domain you use for SPF or DKIM authentication.
3. Add the TXT or CNAME record it gives you at your domain host. Google says verification is usually immediate but can take up to 10 minutes.
4. Open the compliance status view. Google says it shows whether you meet its sender requirements, with each item marked Compliant, Needs work, or No data found.
5. Check the spam rate. Gmail's guidelines say to keep the user-reported spam rate below 0.3% and recommend staying below 0.1%.

Expect gaps. Google says data may be missing when daily volume is too low, so a company sending a few dozen emails a day may see "No data found" for weeks. That isn't a problem by itself. For small senders, the seed test and Show original check are the main tools, and Postmaster becomes useful once you send newsletters or reminders in volume.

Step 5: Read bounce messages and your sending logs

Spam folders are only half the picture. Some mail never arrives anywhere because the receiving server refuses it, and the evidence sits in places owners rarely look.

1. Search your own inbox for bounce notices. Look for "Undeliverable", "Delivery Status Notification" or "Mail delivery failed". The notice usually names the reason in plain words near the top, such as an unknown recipient, a full mailbox, or a message blocked for failing authentication. Read the reason before deleting it.
2. Open the sending log in your CRM or marketing tool. Most show delivered, bounced and complained statuses per message, and keep a suppression list of addresses they've stopped mailing. If a regular customer's address is on that list, nothing you send from that system reaches them until it's fixed.
3. Separate hard bounces from soft ones. A hard bounce (the address doesn't exist) should be removed or corrected by calling the customer. A soft bounce (temporary problem) usually clears on its own; if the same address soft-bounces for weeks, treat it like a hard one.
4. Look for patterns. If bounces cluster at one provider, such as every Outlook.com address, the problem is likely your authentication or reputation with that provider, not the individual customers.

Common mistakes and how to fix them

• Website forms that pretend to be the customer. Many form plugins send the notification "from" the customer's own address. Your domain can't authenticate a Gmail address, so these fail DMARC and often vanish. Fix: send form notifications from an address at your domain and put the customer's address in the Reply-To field.
• The CRM sends with no authentication for your domain. Reminders and invoices go out signed only by the vendor. Fix: complete the vendor's custom domain or sender authentication setup, which usually means adding two or three DNS records.
• Marketing to old lists. Emailing customers from five years ago, or a purchased list, drives up complaints and bounces. Fix: mail people who did business with you or asked to hear from you, include an unsubscribe link, and remove addresses that bounce.
• Asking customers to check spam instead of fixing it. It works for one customer and fails for the next hundred. Fix: find the failing sender with the steps above.
• Changing hosts without re-testing. A new email host or CRM brings new sending servers. Fix: rerun the seed test the same day you switch.

Next steps

Write down the results of today's test and set a reminder to repeat it next quarter. If you found failures, fix the authentication records first and retest the same day, since DNS changes often take effect within minutes to hours. If you don't have your own domain email yet, start with how to get a business email address. When we set up business email or email marketing for a client, every system that sends as the domain gets authenticated and tested this way before it goes live.

Frequently asked questions