Deliverability guide
Why emails go to spam—and what to fix first.
Spam placement is rarely one mysterious setting. It is usually a combination of trust signals that tell a mailbox provider whether your message is safe, wanted, and genuinely from your business.
A practical starting guide from Cyber Bounds Inc.
Start with the question behind the problem
“My emails are going to spam” can mean a few different things. A one-to-one sales email may land in junk at Microsoft. A newsletter may reach Promotions or spam at Gmail. Password reset messages may be blocked. Or customers may be reporting non-delivery because an address was typed incorrectly or an old sender was used.
Before changing anything, separate the symptoms by email type, sending platform, domain, recipient provider, and time period. That makes it possible to see whether the problem is authentication, reputation, list quality, content, configuration, or something else.
Make sure the sender can be verified
Authentication is the first foundation. It does not guarantee inbox placement, but weak or missing authentication makes it much harder for mailbox providers to trust a message.
SPF: the approved-sender list
An SPF record in DNS lists services that are allowed to send mail for a domain. It should reflect the platforms you actually use: your workspace provider, marketing platform, CRM, help desk, billing system, and any application that sends as your business.
DKIM: the signed message
DKIM attaches a digital signature to mail. A receiving server can use the public key in DNS to check that the message was signed by an approved system and has not changed after signing.
DMARC: the policy and feedback loop
DMARC brings SPF and DKIM together. It tells a recipient server what to do when authentication does not line up with your visible sending domain, and it can send reports that reveal who is trying to use your domain.
Then look at sending reputation and audience signals
Mailbox providers also learn from sending patterns and recipient behaviour. If a high proportion of recipients delete messages without reading them, mark them as spam, or never engage, your future mail may be treated with more caution. Sudden volume changes, old lists, frequent bounces, and unclear permission can all contribute.
- Send to people who expect to hear from you.
- Remove or suppress addresses that consistently bounce or do not engage.
- Warm up new sending domains and new platforms gradually.
- Use a consistent From name and address that recipients recognize.
- Do not mix transactional email and high-volume promotional email without a deliberate domain strategy.
Do not overlook the systems around your inbox
A business can have perfect marketing authentication and still struggle with everyday mail. Check forwarding rules, compromised accounts, old website forms, CRM connections, shared mailboxes, and applications that are still configured with an outdated From address. These sources can create authentication failures or suspicious traffic without appearing in your marketing dashboard.
What to do first
- Run a free DNS check to see whether SPF, common DKIM selectors, and DMARC are visibly published.
- List every system that sends email as your domain.
- Inspect actual message headers from a test sent to Gmail and Outlook to see which checks pass or fail.
- Fix the highest-risk authentication and configuration issues before changing campaign content.
- Monitor the effect and avoid making several unrelated changes at once.
When a full deliverability audit is the better move
If revenue-critical email is missing the inbox, different platforms are involved, or your internal team needs a reliable technical plan, an email deliverability audit gives you more than a public DNS snapshot. It maps the systems, checks the details, and lays out the safest fixes in priority order.