Why are emails from new dedicated IPs and domains landing in spam?
Matthew Whittaker
Co-founder & CTO, Suped
Published 23 May 2025
Updated 19 Aug 2025
7 min read
When you start sending emails from a brand new dedicated IP address or domain, it can be frustrating to find your messages landing directly in spam folders. This isn't necessarily a sign that you're doing something wrong. Instead, it's a common initial hurdle faced by all new senders.
Mailbox providers, like Google and Yahoo, are highly cautious of new sending infrastructure. Without any prior sending history, a new IP and domain lack the reputation needed to be immediately trusted. They operate on a 'guilty until proven innocent' principle to combat unsolicited bulk email (UCE) and spam.
The challenge of a new reputation
A new dedicated IP address, often referred to as a 'cold' IP, has no established reputation with internet service providers (ISPs). When you suddenly begin sending volume from it, ISPs view this activity with suspicion, as it can mimic the behavior of spammers trying to quickly deploy large amounts of unwanted mail. This lack of history is a significant red flag for spam filters.
Similarly, a new domain name also starts with a neutral, or even slightly negative, reputation. Email service providers (ESPs) and ISPs observe sending patterns and recipient engagement associated with your domain to build its reputation over time. Without any historical data, your domain is unproven, making filters more likely to send your emails to the spam folder. This is why emails from new domains can go to spam even with low sending volumes.
The spam filters are constantly evolving, and their algorithms are designed to detect anomalous sending patterns. A sudden surge in email volume from a previously inactive IP or domain is a classic anomaly. They need to see a consistent, gradual increase in sending with positive engagement metrics to classify your emails as legitimate. This applies to both your IP and your domain, as your sender reputation impacts deliverability.
Understanding cold IPs and domains
When you acquire a new dedicated IP or domain, it lacks any established history with mailbox providers. This 'cold' status means it's initially seen with skepticism. Mailbox providers err on the side of caution, often routing emails from unproven senders directly to the spam or junk folder to protect their users from potential abuse.
It's a necessary security measure in the email ecosystem, but it can be challenging for legitimate senders who are just starting out or migrating their email services. Patience and strategic volume management are key during this initial phase.
Importance of IP and domain warming
The solution to overcoming this initial suspicion is a process called IP and domain warming (or warm-up). This involves gradually increasing your email sending volume over several weeks or even months. The goal is to build a positive sending reputation by demonstrating consistent, wanted email activity to mailbox providers. This is a critical step to stop emails going to spam.
During the warming phase, you should start with small volumes of emails to highly engaged subscribers. As your reputation improves and mailbox providers see positive engagement (opens, clicks, replies, not marked as spam), you can slowly increase the daily volume. This gradual ramp-up allows filters to learn that your emails are legitimate and desired by recipients. Understanding what causes emails to go to spam when migrating is essential for a smooth transition.
It's important to be patient and follow a structured warming plan. Rushing the process or sending too much volume too soon can backfire, leading to blocklists (or blacklists) and severe deliverability issues. Each mailbox provider, such as Microsoft, has its own sensitivity to new IPs, and a slow, steady approach yields the best long-term results.
Without warming
Sudden volume: Sending large email volumes from a new IP or domain immediately triggers spam filters due to the lack of history.
Low trust: ISPs have no data to confirm you're a legitimate sender, leading to default spam placement.
Gradual increase: Sending small volumes initially and slowly ramping up helps build trust.
Positive reputation: Consistent positive engagement signals to ISPs that your emails are wanted.
Improved deliverability: Over time, more of your emails will reach the inbox, avoiding the spam folder.
Essential authentication protocols
Even with a warming strategy, proper email authentication is non-negotiable. SPF, DKIM, and DMARC are fundamental protocols that verify your sending identity and help prevent spoofing and phishing. Without these, your emails are much more likely to be flagged as spam, regardless of your IP or domain age. It's crucial to ensure these are correctly configured from day one.
SPF (Sender Policy Framework) allows you to specify which IP addresses are authorized to send email on behalf of your domain. DKIM (DomainKeys Identified Mail) provides a way for senders to digitally sign their emails, allowing receivers to verify that the email was sent by an authorized sender and hasn't been tampered with. DMARC (Domain-based Message Authentication, Reporting, & Conformance) builds upon SPF and DKIM, telling receiving servers how to handle emails that fail authentication and providing reporting on email authentication results. Even transactional emails with passing authentication can land in spam if other factors are poor.
While authentication is vital, it's not a silver bullet. Mailbox providers like Gmail especially scrutinize new domains, even with perfect authentication. They combine authentication results with IP and domain reputation, content analysis, and recipient engagement signals to make deliverability decisions. A strong DMARC policy offers significant benefits.
Protocol
Purpose
Key function
SPF (Sender Policy Framework)
Verifies authorized sending IPs for your domain. Google and Yahoo require it.
TXT record listing approved sending servers.
DKIM (DomainKeys Identified Mail)
Ensures email integrity and sender authenticity. Microsoft and other major providers use it.
Digital signature attached to emails, verified via DNS.
Defines how receivers handle emails failing SPF or DKIM, and provides aggregate reports. Critical for domain reputation.
Policy (p=none, quarantine, reject) and reporting mechanism.
Content quality and engagement
Beyond technical configurations, the content of your emails and how recipients interact with them play a huge role. Even with a new, properly warmed IP and domain, spammy content can trigger filters. This includes overuse of certain keywords, excessive images, broken links, or misleading subject lines. Ensure your content is clean, relevant, and provides clear value to the recipient. Regularly checking your email deliverability is important.
Recipient engagement is arguably the most powerful factor for long-term deliverability. When recipients open, click, reply to, or move your emails to their inbox (if they landed in spam), these positive signals tell mailbox providers that your emails are wanted. Conversely, if recipients mark your emails as spam, delete them without opening, or simply ignore them, it will quickly degrade your domain reputation.
For new IPs and domains, even a single spam complaint can have a disproportionately negative effect. During the warming phase, focus on sending to your most engaged segments to maximize positive interactions and minimize complaints. This proactive approach helps build a robust sender reputation that can withstand occasional bumps down the line. It's especially crucial for DMARC failures and spam during domain warm-up.
Content quality and recipient engagement
Even with perfect technical setup, poor content or negative recipient actions can send emails to spam. Spam filters analyze content for suspicious keywords, formatting, and links. More importantly, mailbox providers track how recipients interact with your emails. If users frequently delete, ignore, or mark your emails as spam, your reputation will suffer, regardless of your authentication or warming efforts.
Focus on highly engaged subscribers, segment your lists, and provide valuable content. Avoid using spam trigger words or overly promotional language, especially when building your initial reputation.
Building a trusted sender profile
Emails from new dedicated IPs and domains landing in spam is a temporary, albeit common, challenge. It's a clear signal that you need to focus on establishing a strong, positive sender reputation. This means committing to a methodical IP and domain warming plan, ensuring all your authentication protocols are flawlessly set up, and consistently delivering high-quality, engaging content to your recipients.
Remember, building trust with mailbox providers takes time and consistent effort. By prioritizing these elements, you'll lay a solid foundation for excellent email deliverability, ensuring your messages reach the inbox and connect with your audience as intended.
Views from the trenches
Best practices
Implement a slow and steady IP and domain warming schedule, starting with very low volumes to highly engaged segments.
Ensure all DNS records for SPF, DKIM, and DMARC are correctly configured and validated before sending any volume.
Monitor your deliverability metrics closely, including open rates, click rates, and spam complaint rates, especially during the warm-up phase.
Regularly check for any blocklist (or blacklist) listings of your new IP or domain.
Focus on sending valuable, non-promotional content initially to encourage positive recipient engagement.
Common pitfalls
Sending large volumes immediately from a new dedicated IP or domain, triggering spam filters.
Ignoring IP and domain warming protocols, leading to reputation damage and poor deliverability.
Neglecting email authentication (SPF, DKIM, DMARC), which prevents mailbox providers from trusting your emails.
Sending to unengaged or old lists during warm-up, resulting in high bounce rates and spam complaints.
Using aggressive or 'spammy' content, even for test sends, which can prematurely flag your new sending identity.
Expert tips
Segment your most active subscribers for the initial warm-up sends to maximize positive engagement signals.
Use email deliverability testing tools to verify your email setup and inbox placement before large sends.
Be patient, as establishing a strong reputation can take several weeks or even months for high-volume senders.
Review Google Postmaster Tools and similar services for insights into your domain's reputation.
If issues arise, pause sending, diagnose the problem, and only resume once the fix is confirmed.
Marketer view
Marketer from Email Geeks says that test sends from a new dedicated IP or domain often land in spam, and it's important to train the inbox that the mail is wanted.
2019-05-15 - Email Geeks
Expert view
Expert from Email Geeks says that a proper IP warm-up exercise is crucial for new sending infrastructure to establish a positive reputation.
Google and 
Yahoo require it.
Microsoft and other major providers use it.
