Gmail usually gives a reason
Open the message in Gmail's Spam folder and read the banner above it. Gmail may mention a suspicious link, unauthenticated sender, previous spam reports or another specific concern. That explanation is the best place to begin.
First checks
Rule out the common causes
- Use your assigned UKC outgoing mail server. Send through authenticated SMTP with the complete email address as the username. Avoid sending directly through a home broadband connection.
- Check the From address. It should be a real address on your domain and should match the service authorised to send the message.
- Review links and attachments. Remove unexpected shortened links, requests for passwords or payment details, and unnecessary attachments.
- Send only expected email. Sudden bursts, old mailing lists and messages to people who did not ask to hear from you can damage delivery.
- Read any delivery failure. A rejection or bounce normally contains an SMTP code and explanation that identifies a different problem from Spam-folder placement.
Domain trust
Check your email authentication
- SPF
- Lists the services allowed to send email for your domain
- DKIM
- Adds a verified digital signature to outgoing messages
- DMARC
- Tells receiving providers how SPF and DKIM should align with the visible From domain
Google requires SPF or DKIM for all senders to Gmail and recommends using SPF, DKIM and DMARC together. If you use another mail platform, newsletter service or website form, every legitimate sender must be included in the authentication setup.
Review DNS records“Not spam” helps, but it is not the whole fix
If the recipient trusts the message, they can select Not spam and add the sender to Contacts. This helps that recipient, but authentication or reputation problems must still be corrected at the sender.
Newsletters and campaigns
Bulk email needs additional care
- Use a reputable mailing platform rather than a normal mailbox.
- Send only to confirmed subscribers and make unsubscribing simple.
- Keep sending volume steady instead of introducing sudden spikes.
- At meaningful Gmail volumes, use Google Postmaster Tools to monitor authentication, reputation and spam reports.
Helpdesk diagnosis
Send us one complete example
- Sender
- The full From email address
- Recipient
- The Gmail address, partly hidden if preferred
- Time
- Date, time and timezone sent
- Server
- The outgoing mail server used
- Evidence
- Gmail's reason banner, any bounce text and the message headers, with passwords removed
Still reaching Gmail's Spam folder?
Send us one recent example and the details above. We can check the domain records and server logs without needing your mailbox password.
Ask UKC to investigate