When Gmail states your sender domain is spam - Online Help | Zoho Campaigns

When Gmail states your sender domain is spam

Sender domain reputation matters a great deal in successful inbox placement. If Gmail shows the warning “Lots of messages from yourdomain.com were identified as spam in the past,” it means recipients have been reporting your mail as spam and Gmail no longer trusts your domain — the fix is to lower your spam-complaint rate, authenticate your domain, and send only to people who want your email. Numerous factors like email subject and content, sender domain reputation, and mailing list quality play a vital role in building up domain reputation. ESPs and ISPs measure reputation for every sender domain, based on their sending practices. The domain reputation decreases whenever the email sending practice does not meet the required standard. When the reputation falls below a stipulated threshold, your sender domain may get blacklisted.

Why Gmail says your sender domain is spam – An infographic.

When Gmail views some practices of a sender domain as suspicious or when the reputation of a sender domain decreases beyond a particular threshold, all emails from your sender domain will land in spam and users will receive the following message:
“Lots of messages from yourdomain.com were identified as spam in the past”
spam-gmail
The following are a set of possible scenarios which may have led to the above notification. Make sure to avoid these practices in the future:
  1. Using a secondary domain (other than the domain of your official website) to send emails. Your contacts may not recognize the relationship between the two different domains. If you still want to use a secondary domain, make sure to include the signup URL in the footer of the email for the contact to verify the connection between the domains, and authenticate that domain (see below) so Gmail can tie it back to you.

  2. Your email subject may not convey the message you actually intended to deliver to your contacts. Due to this, your contacts may feel misled and mark you as spam. Ensure that your subject and content are relevant to each other.

  3. Zoho Campaigns strongly recommends that you follow permission-based email marketing. Ensure that all of your contacts are opt-in and that you have obtained their consent to send newsletters.

  4. Your mailing list may contain old and idle contacts with whom you haven’t emailed in the last three months. When you send an email after a long gap, they may not recognize you and hence may mark your email as spam. Convert inactive contacts into opt-in contacts by sending re-engagement emails and clean your list of uninterested contacts. Continuing to mail people who never open your email drags down your reputation for everyone on the list.

  5. Avoid flooding the inboxes of your contacts with several emails in a short duration. This creates more chances of Gmail labeling your emails as spam. Always give regular intervals between your consecutive campaigns.

  6. Seeking sensitive information in the email content or in an immediate landing page from a URL is considered spam triggering. So, your contacts may have felt it suspicious. If it is necessary to collect sensitive information, then you can add an optional step to ask such details while your contacts sign up.

  7. Content still matters, but less than it once did. Overusing promotional words such as buy, order, discount, clearance, dear friend, as seen on, please help, free, offer, desperate, or additional income can raise the suspicion of your contacts or Gmail. On today’s machine-learning filters a single trigger word won’t sink a trusted sender, but combined with weak reputation it adds up — so keep subject lines and content clear and honest.

Authenticate your domain and stay within Gmail’s limits

Gmail now treats authentication and a low complaint rate as baseline requirements, not nice-to-haves. Under Google’s bulk sender requirements (in force since February 2024), anyone sending to Gmail users should set up SPF, DKIM, and DMARC; bulk senders (roughly 5,000+ messages a day to Gmail) must also include a one-click unsubscribe option and keep their spam-complaint rate below 0.3% — ideally under 0.1%. Since late 2025, Gmail rejects non-compliant mail outright rather than quietly filtering it, so meeting these requirements is the foundation of a healthy domain reputation.

Suggestions from our deliverability team

The reputation of your domain might have been reduced due to any of the above scenarios. Senders can make use of the given suggestions to avoid further decline in their domain reputation.
  1. Gently remind your contacts to add your sender address to their address book or safe senders’ list.

  2. Ensure that your domain has a good reputation in Gmail by using Postmaster Tools to analyze your email performance and other vital factors. As of late 2025, Postmaster Tools v2 replaced the old “Domain Reputation” score with a Compliance Status dashboard and a Spam Rate dashboard — check compliance first, then confirm your spam rate is under the 0.3% threshold (aim for below 0.1%). Set up the Gmail Feedback Loop as well to see which specific campaigns are being reported.

  3. Incorporate the following lines as footer data while sending out email campaigns, especially while sending to Gmail users:
    1. If you are not interested in receiving our emails, you can unsubscribe.
    2. If you see this email in the Promotions tab, kindly drag and drop it into your Primary tab so that our future emails will arrive in your inbox.
    3. You’re receiving this email as you have signed up with us at “sign up URL”.
    4. If you see this email in your spam folder, kindly add us to your address book for our regular communication.