Summary
Rebuilding domain/IP reputation after switching from Mailchimp is challenging due to the loss of established sender reputation, disrupted sending patterns, and potential issues with authentication and list hygiene. Mailbox providers view changes in sending behavior with suspicion, often triggering spam filters. Core issues include starting with a 'cold' IP and domain reputation, inconsistent sending practices, and improper authentication setup (SPF, DKIM, DMARC). Existing problems like low engagement, high bounce/complaint rates, and poor list hygiene become more apparent and negatively impact deliverability on the new platform. The process for building back reputation requires implementing a careful IP warming strategy, cleaning the email list, authenticating, and consistently monitoring sending behaviour and engagement rates.
Key findings
- Reputation Reset: Migrating from Mailchimp equates to restarting with a 'cold' IP and domain reputation, regardless of prior sending history.
- Suspicion of New Patterns: Inconsistent sending practices and disrupted patterns are viewed skeptically by ISPs, impacting deliverability.
- Authentication Gaps: Faulty or incomplete authentication (SPF, DKIM, DMARC) on the new ESP damages credibility and deliverability.
- List Hygiene Matters: Poorly maintained email lists with unengaged or invalid addresses trigger increased bounces and complaints, hurting reputation.
- The Age of your Domain counts: The domain age matters, switching to a new platform won't fix a domain or email address if it's new or has a bad sending history.
- Google's Soft Bounce Handling is Important: It is important to know the full reason for soft bounces and that sending to often full inboxes may hurt the sender's reputation.
Key considerations
- Implement IP Warming: Follow a strategic IP warming plan to incrementally increase sending volume and establish a positive reputation.
- Clean Your List: Improve list hygiene by removing unengaged, inactive, or invalid email addresses.
- Authenticate: Properly configure SPF, DKIM, and DMARC records to confirm email authenticity with mailbox providers.
- Monitor Sending: Carefully monitor sending volume, bounce rates, complaint rates, and engagement metrics to detect and address issues.
- MX Records are important: Ensure that you are sending from an email and domain with valid MX records to confirm to mailbox providers you're sending from a legitimate and monitored email address.
- Explicit Permission: Ensure you have permission to send to the emails and aren't sending to emails just because they 'logged in via Google', be sure to get their explicit email permission.
What email marketers say
11 marketer opinions
Switching from Mailchimp to a new email service provider (ESP) often leads to deliverability challenges due to the loss of established sender reputation. Mailbox providers view the change in sending patterns with suspicion, potentially triggering spam filters. Key factors contributing to this issue include starting with a 'cold' IP and domain reputation, inconsistent sending practices, and improper authentication setup (SPF, DKIM, DMARC). Furthermore, issues like low engagement, high bounce/complaint rates, and poor list hygiene, which may have been masked by Mailchimp's infrastructure, become more apparent and negatively impact deliverability on the new platform. Rebuilding reputation requires a strategic approach focusing on IP warming, list cleaning, authentication, and consistent sending behavior.
Key opinions
- Reputation Loss: Switching ESPs means leaving behind the established sender reputation associated with Mailchimp's infrastructure, essentially starting with a 'cold' reputation.
- Sending Patterns: Disrupted sending patterns trigger suspicion from ISPs, leading to deliverability problems.
- Authentication Issues: Incorrect or missing authentication setup (SPF, DKIM, DMARC) on the new platform significantly hurts reputation.
- List Hygiene: Poor list hygiene, including unengaged users, increases bounce and complaint rates, negatively impacting deliverability.
- Sudden Change in Volume: Sudden spikes in email volume without a proper warm-up can flag your new IP address as a potential spam source.
Key considerations
- IP Warming: Implement a gradual IP warming strategy to establish a positive sending reputation with mailbox providers.
- List Cleaning: Clean your email list to remove unengaged users and reduce bounce/complaint rates.
- Authentication: Ensure proper authentication (SPF, DKIM, DMARC) is correctly configured on the new platform.
- Engagement Monitoring: Closely monitor engagement metrics (open rates, click-through rates) to identify and address any potential issues.
- Consistent Sending: Maintain consistent sending volume and frequency to establish a predictable sending pattern.
- Permission Practices: Ensure that you have explicit permission to send to all recipients, avoiding emails to 'login via Google' accounts without clear consent.
Marketer view
Email marketer from Litmus Blog responds that you should focus on authentication and list hygiene, ensuring the new platform's settings match the old and you're not mailing to unengaged users. A new platform shines a light on existing issues.
10 Feb 2025 - Litmus Blog
Marketer view
Email marketer from ActiveCampaign Blog responds that after switching ESPs, it's essential to monitor bounce rates, complaint rates, and engagement metrics closely. He shares that a sudden increase in bounces or complaints can negatively impact your reputation and trigger spam filters, so careful list management is crucial.
15 Apr 2025 - ActiveCampaign Blog
What the experts say
7 expert opinions
Rebuilding domain/IP reputation after switching from Mailchimp presents challenges related to authentication, sending practices, and handling bounces. Sending from domains with missing MX records is a red flag. Google's treatment of soft bounces (especially full mailboxes) is evolving, and it's crucial to understand bounce message details. Furthermore, gradual IP warming is essential when migrating to a new ESP to establish trust with mailbox providers. Proper authentication (SPF, DKIM, DMARC) is also crucial to prove legitimacy.
Key opinions
- MX Record Importance: Sending from a domain without an MX record is a significant negative signal.
- Google Bounce Handling: Google's handling of full mailbox bounces is aggressive, but the impact of resending to 4xx addresses is unclear.
- Authentication Critical: Proper SPF, DKIM, and DMARC authentication is crucial for verifying sender legitimacy after switching platforms.
- IP Warm-up Needed: Slowly ramping up sending volume when migrating to a new ESP is important for assessing and establishing a good sending reputation.
- Bounce Message Analysis: Understanding the full text of bounce messages is crucial for identifying the underlying cause of deliverability problems.
Key considerations
- Verify MX Records: Ensure the sending domain has a valid MX record configured.
- Monitor Bounce Messages: Carefully analyze the full text of bounce messages to understand the reason for delivery failures.
- Implement IP Warming: Gradually increase sending volume on the new ESP to build a positive reputation.
- Check Authentication: Verify that SPF, DKIM, and DMARC records are correctly configured on the new platform.
- Manage Soft Bounces: Implement strategies for handling soft bounces, considering the evolving practices of mailbox providers.
Expert view
Expert from Email Geeks responds that she doesn’t know how much Google counts resending to 4xy addresses as a knock on reputation- probably not too much as they’re telling you it’s ok to resend
30 Jun 2022 - Email Geeks
Expert view
Expert from Email Geeks suggests that sending from a domain with no MX record is a very bad signal. She also mentions that Google soft bounces are often rate limiting based on reputation, but can also be abandoned accounts. The full text of the bounce message is needed to identify the underlying reason for the bounce.
15 Jun 2023 - Email Geeks
What the documentation says
4 technical articles
Rebuilding domain/IP reputation after switching from Mailchimp, as described by documentation from various sources, necessitates a strategic approach centered on IP warming, authentication, and responsible sending practices. Since sender reputation is tied to IP addresses, migrating away from Mailchimp's shared infrastructure essentially means starting with a new reputation. A crucial step is gradually increasing email volume (IP warming) to allow mailbox providers to learn that the IP is sending legitimate email. Alongside IP warming, it's essential to ensure proper authentication, send wanted content, and avoid sending to old or unengaged email addresses to build a positive sender reputation with ISPs.
Key findings
- New IP, New Reputation: Switching from Mailchimp’s shared IP to a dedicated or different shared IP means starting with a new sender reputation.
- IP Warming Importance: Gradually increasing email volume (IP warming) is crucial for building trust with mailbox providers and demonstrating legitimate sending behavior.
- Authentication is Key: Proper email authentication (SPF, DKIM, DMARC) is essential for verifying sender identity and improving deliverability after migration.
- Content Relevance: Sending wanted content ensures positive engagement, which contributes to a better sender reputation and improved deliverability.
- List Hygiene: Avoiding sending to old and unengaged email addresses improves deliverability and protects sender reputation.
Key considerations
- Implement IP Warming: Follow a structured IP warming plan to gradually increase sending volume and establish a positive reputation.
- Authenticate Your Emails: Properly configure SPF, DKIM, and DMARC records to verify email authenticity.
- Send Relevant Content: Ensure the emails you send are wanted and relevant to the recipients' interests.
- Clean Your Email List: Remove old, inactive, and unengaged email addresses from your list.
- Monitor Deliverability: Track deliverability rates, bounces, and complaints closely to identify and address any potential issues.
Technical article
Documentation from SparkPost shares that sender reputation is closely tied to IP addresses. When switching from Mailchimp's shared IP infrastructure to a dedicated IP or a different shared pool, you're essentially starting with a new reputation. They recommend following IP warming best practices to gradually establish trust.
9 Aug 2022 - SparkPost Documentation
Technical article
Documentation from Mailjet explains that using a new IP address for sending emails requires a warm-up period. They highlight the importance of gradually increasing the sending volume, monitoring deliverability rates, and actively managing bounces and complaints to build a positive reputation with ISPs.
4 Mar 2022 - Mailjet Documentation
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