Why are emails from new dedicated IPs and domains landing in spam?
Matthew Whittaker
Co-founder & CTO, Suped
Published 23 May 2025
Updated 14 Aug 2025
9 min read
Summary
Emails from new dedicated IP addresses and domains frequently land in spam folders due to a lack of established sender reputation. Internet service providers (ISPs) view new sending origins with suspicion, as they lack historical data to prove legitimacy. This is a normal, expected part of the email sending lifecycle and requires a strategic approach, primarily through a process known as IP and domain warming, to build trust with mailbox providers. Without warming, even legitimate emails can be flagged as spam, impacting deliverability.
Key findings
Lack of reputation: New IPs and domains have no sending history, making it difficult for ISPs to trust them immediately. This absence of a sender reputation often leads to emails being filtered into spam.
ISP suspicion: Mailbox providers are cautious about new senders, as they could be spammers. They actively monitor initial sending behavior closely for any red flags. Microsoft, for instance, is particularly sensitive to sudden volume increases from new IPs.
Warm-up necessity: A gradual increase in sending volume, known as IP and domain warming, is crucial. This process slowly builds a positive reputation with ISPs, demonstrating legitimate sending practices.
Content and engagement: Even with warming, email content and recipient engagement play a significant role. Generic or test-like content can trigger spam filters, especially on new sending infrastructure.
Key considerations
Implement an IP warm-up strategy: Develop a structured plan to gradually increase your sending volume, allowing ISPs to recognize and trust your new IP and domain. You can learn more about how to warm up a new IP in our guides.
Monitor your sender reputation: Regularly check your IP and domain reputation. Tools can help you track your sender score and identify if you're on any blocklists (or blacklists). Monitoring is key to proactively addressing issues.
Ensure proper authentication: Verify that your SPF, DKIM, and DMARC records are correctly configured. These authentication protocols are essential for proving the legitimacy of your emails to ISPs.
Send engaging content: Focus on sending valuable and relevant content to a highly engaged audience during the warm-up phase. High open and click rates improve your sender reputation. For more tips on avoiding spam folders, check out this guide from EmailTooltester
Be patient: Building a solid sender reputation takes time and consistent effort. There are various factors that can cause emails to go to spam, and often, patience is key.
What email marketers say
Email marketers commonly encounter deliverability challenges when starting with new dedicated IPs and domains. Their experiences highlight the critical role of reputation, the necessity of a proper warm-up process, and the potential pitfalls of rushing or neglecting foundational steps. Marketers emphasize that initial spam folder placement for new sending infrastructure is often normal but underscores the need for strategic volume increases and diligent monitoring to establish trust with ISPs. Ignoring these steps can lead to severe long-term deliverability issues.
Key opinions
Expected behavior: It is widely accepted that emails from new domains and IPs will initially land in the spam folder, even for legitimate test sends.
Warm-up is non-negotiable: A cautious and deliberate IP warm-up process is crucial to avoid severe reputation damage, especially with major mailbox providers like Google.
Small starts are effective: Starting with very low volumes (e.g., 10 emails to Gmail) and gradually increasing is a proven method for building trust.
Test content can be problematic: Emails resembling generic 'test content' can look suspicious to ISPs, further contributing to spam placement for new senders.
Key considerations
Prioritize warm-up: Do not skip or rush the IP warm-up phase, as it is foundational for establishing a good sender reputation. This is especially true when migrating to a new ESP, as outlined in our guide on deliverability issues during ESP migration and IP warming.
Avoid immediate large volumes: Sending a high volume of emails from a cold IP or domain can quickly lead to blocklisting and severe deliverability problems. Even a few test sends can trigger filters if the IP is too new.
Understand ISP behavior: Recognize that ISPs, particularly major ones like Gmail, are highly vigilant with new IPs and domains due to spam concerns. Their algorithms need time to learn and trust new sending patterns. You can find more detail on this in our article prevent your emails from going to spam
Monitor blocklists: Keep a close eye on various blocklists and blacklists as you warm up. Being listed can significantly hamper your efforts and require removal processes.
Marketer view
Marketer from Email Geeks explains that they initially suspected some level of filtering from ISPs when deploying from a cold IP and domain. They understood the need to 'train' the inbox that the mail was wanted. This aligns with the common understanding that new sending infrastructure lacks inherent trust.
15 May 2019 - Email Geeks
Marketer view
Marketer from Email Geeks mentions that they are sending very low volumes, only a few test emails to themselves. Their domain is brand new and not previously used on other ESPs. This illustrates a typical scenario for new senders, where even minimal volume can lead to spam folder placement due to the lack of history and trust.
15 May 2019 - Email Geeks
What the experts say
Experts universally agree that emails from new dedicated IP addresses and domains face an uphill battle to reach the inbox due to a lack of established trust with Internet Service Providers (ISPs). The core message revolves around the indispensable nature of IP and domain warming to gradually build a positive sender reputation. They caution that rushing this process or neglecting it entirely will inevitably lead to emails being flagged as spam, even if the content is legitimate, underscoring that patience and a strategic ramp-up are paramount for long-term deliverability success.
Key opinions
Warming is fundamental: The most emphasized point is the necessity of an IP warm-up exercise for any new IP or domain.
Not unexpected: Spam folder placement for new sending infrastructure, especially by Gmail, is a common and predictable outcome due to lack of prior interaction.
Risk of poor reputation: Failing to warm up cautiously can lead to significant and long-lasting reputation damage with major mailbox providers like Google.
Volume sensitivity: ISPs are particularly sensitive to the volume of emails sent from new IPs and domains. Sending too much too soon is a major red flag.
Avoid 'spammer' signals: Be mindful that sending sparse 'test' content from a new domain/IP can mimic spammer behavior and further hinder initial deliverability. Ensure your emails look legitimate, even during early testing phases.
Prioritize inbox placement over volume: The immediate goal for new infrastructure is to land in the inbox, not to send large volumes. Quality and recipient engagement are key to building positive reputation. This applies whether you are using a dedicated IP or a shared IP
Long-term perspective: Understand that building a strong sender reputation is a continuous process. Initial spam placement is a hurdle, but consistent good practices will eventually yield results. Our guide on understanding your email domain reputation can provide further insight.
Expert view
Expert from Email Geeks asks about the age of the domain. This indicates that the recency of a domain's registration is a significant factor in how ISPs perceive its trustworthiness. Newer domains are viewed with higher suspicion until they prove their legitimacy through consistent, positive sending behavior.
15 May 2019 - Email Geeks
Expert view
Expert from Email Geeks inquires about the sending volume. This highlights that the volume of email sent from a new IP or domain is a critical metric ISPs use to assess sender intent. A sudden high volume from an unknown source is a classic indicator of spamming activity.
15 May 2019 - Email Geeks
What the documentation says
Official documentation and industry research consistently underscore that new dedicated IPs and domains inherently lack a sender reputation, which is why their emails are often routed to spam folders. Mailbox providers prioritize protecting their users from unwanted mail, and without a proven history of good sending practices, new senders are treated with caution. The emphasis is invariably on controlled volume increases, consistent engagement, and adherence to email authentication standards to build the necessary trust over time. Failing to follow these established guidelines can lead to severe and prolonged deliverability challenges.
Key findings
Reputation is paramount: A good sender reputation, built over time, is the most critical factor for inbox placement. New IPs and domains start with a neutral or unknown reputation, leading to initial spam filtering.
Warm-up protocols: Industry best practices dictate a warm-up period for new IPs and domains, involving a gradual increase in sending volume to engaged recipients.
Authentication is foundational: Proper configuration of SPF, DKIM, and DMARC is essential for any sender, but especially for new ones, to prove legitimacy to ISPs.
Engagement signals: Positive engagement (opens, clicks, replies) helps build reputation, while negative engagement (complaints, unsubscribes, bounces) can quickly derail it.
Key considerations
Adhere strictly to warm-up schedules: Do not deviate from recommended warm-up volumes, even if initial results seem positive. Over-sending prematurely can damage your IP and domain reputation. Find out more about common deliverability issues during warmup.
Segment your audience: During warm-up, send only to your most active and engaged subscribers to maximize positive engagement signals.
Maintain consistent sending: Once warmed, maintaining a consistent sending volume and frequency helps sustain a good reputation. Inconsistent sending can sometimes trigger reputation checks. We also have a guide on dedicated versus shared IPs
Monitor feedback loops: Sign up for ISP feedback loops (FBLs) to receive reports on spam complaints, allowing you to quickly identify and address issues. This is especially important as you increase volume.
Technical article
Documentation from Mailgun states that a poor sender reputation can lead to emails being placed in the spam folder. This is particularly relevant for new dedicated IPs and domains, as they start with a neutral reputation, making them more susceptible to filtering until a positive history is established through consistent, legitimate sending.
10 Apr 2024 - Mailgun
Technical article
Documentation from Resend explains that dedicated IPs expose your sending behavior more, which can be detrimental if you are a new sender with no sending history. This implies that without a proper warm-up, a new dedicated IP might highlight any poor practices, leading to quicker reputation damage and spam folder placement.
