Summary
Gmail email delays post-SFMC migration commonly arise from sender reputation and IP warming deficiencies. After a migration, Google may temporarily delay messages to assess sender behavior. A short warm-up period and excessive sending volume, authentication problems, and poor list hygiene can negatively impact sender reputation, leading to delays. Domain reputation, shared IP issues and content should also be considered. Google Postmaster Tools and other testing services should be used to monitor deliverability. Mitigation involves gradual IP warm-up, email validation, proper authentication setup, list segmentation, targeted content, and monitoring Postmaster Tools.
Key findings
- Recipient Monitoring: Gmail monitors recipient behavior, causing temporary holds; patience is key.
- IP Warm-up: Insufficient IP warm-up post-migration leads to Gmail mistrust and delays. Gradual warm up is critical to establish trust.
- Sender Reputation: Low sender reputation due to bounces, spam complaints, and poor engagement causes Gmail to delay emails.
- List Hygiene: Poor list hygiene (high bounce rates, unengaged subscribers) damages sender reputation and delays email delivery.
- Authentication: Incorrect or missing SPF, DKIM, and DMARC records cause Gmail to distrust emails, leading to delays and spam filtering.
- SMTP Deferrals: SMTP deferrals are temporary delivery failures due to spam filters or reputation systems; persistent deferrals suggest underlying issues.
- Domain Reputation: A low domain reputation affects deliverability.
- Sending Habits: Changing sending habits trigger delays.
- Content: Spammy words within emails affect deliverability.
- Shared IP: Shared IPs may cause deliverability issues.
Key considerations
- Gradual Warm-up: Implement a gradual IP warm-up strategy, increasing sending volume slowly to build a positive sender reputation.
- List Maintenance: Regularly clean and segment email lists to remove inactive subscribers and reduce bounce rates.
- Authentication Setup: Properly configure SPF, DKIM, and DMARC records to authenticate emails and improve deliverability.
- Continuous Monitoring: Monitor deliverability rates, spam placement, and inbox placement using tools like Litmus Spam Testing and Google Postmaster Tools to identify and address issues proactively.
- Implement DKIM: Ensure DKIM is correctly implemented to authenticate emails and improve deliverability.
- Monitor Postmaster Tools: Actively monitor Google Postmaster Tools to identify and address sender reputation and spam issues.
- Email Validation: Use a validation service to ensure emails being sent are clean.
- Content: Avoid spammy words and make the content personable.
What email marketers say
10 marketer opinions
After migrating to SFMC, delayed Gmail emails often result from sender reputation issues. Key factors include insufficient IP warm-up, poor list hygiene, authentication problems (SPF, DKIM, DMARC), and shared IP reputation. Solutions involve warming up the IP address, cleaning email lists, proper authentication setup, content optimization, list segmentation, validation services and continuous deliverability monitoring using tools like Google Postmaster Tools.
Key opinions
- IP Warm-up: Insufficient IP warm-up post-migration leads to Gmail mistrust and delays.
- Sender Reputation: Low sender reputation due to bounces, spam complaints, and poor engagement causes Gmail to delay emails.
- List Hygiene: Poor list hygiene (high bounce rates, unengaged subscribers) damages sender reputation and delays email delivery.
- Authentication: Incorrect or missing SPF, DKIM, and DMARC records cause Gmail to distrust emails, leading to delays and spam filtering.
- Shared IP: Sending emails from a shared IP can cause email deliverability issues if other users on the IP are blacklisted.
- Domain Reputation: Improve domain reputation by using the Google Postmaster Tools to check if google trusts emails and is not flagging for spam.
- Content: Ensure that the emails being sent do not have spammy words and the content is focused on making emails personable with the goal of getting the subscribers to engage.
Key considerations
- Gradual Warm-up: Implement a gradual IP warm-up strategy, increasing sending volume slowly to build a positive sender reputation.
- List Maintenance: Regularly clean and segment email lists to remove inactive subscribers and reduce bounce rates.
- Authentication Setup: Properly configure SPF, DKIM, and DMARC records to authenticate emails and improve deliverability.
- Continuous Monitoring: Monitor deliverability rates, spam placement, and inbox placement using tools like Litmus Spam Testing and Google Postmaster Tools to identify and address issues proactively.
- Email Validation: Use a validation service to ensure emails being sent are clean.
Marketer view
Email marketer from ActiveCampaign highlights the importance of the content that is being sent, avoid spammy words and make the emails personable with the goal of trying to get user engagement.
21 Aug 2022 - ActiveCampaign
Marketer view
Email marketer from StackOverflow shares the experience of sending emails from a shared IP and suggests it can be a problem as other users on the IP may be blacklisted and affect your deliverability.
2 Apr 2025 - StackOverflow
What the experts say
8 expert opinions
Following an SFMC migration, Gmail delays often indicate reputation or warm-up issues. Gmail may monitor recipient behavior, causing temporary holds. A too-brief warm-up period and excessive sending volume relative to Gmail's acceptance threshold can also lead to delays. Random delivery times might not directly impact engagement. However, Gmail delays often signal underlying reputation problems, and emails ending up in spam also reduce engagement. Inconsistent delivery is expected for a few months post-migration. Mitigation involves gradually increasing sending volume, validating email addresses, encouraging subscribers to safelist the new address, and generally reducing sending speed.
Key opinions
- Recipient Monitoring: Gmail may hold emails to monitor how recipients interact with them, suggesting patience is required.
- Insufficient Warm-up: The warm-up period might have been too short, leading to mistrust from Gmail.
- Sending Volume: Sending volume might be too high for Gmail to accept initially, requiring a reduction.
- Reputation Problems: Gmail delays often indicate underlying reputation issues.
- Normal Growing Pains: Inconsistent delivery is common in the initial months after a migration.
- Changing Sending Habits: Any changes to sending habits trigger delays.
- New IPs: Starting on new IP addresses can cause reputation problems.
Key considerations
- Patience: Allow time for Gmail to assess sender behavior.
- Reduce Sending Volume: Lower sending volume to a level Gmail accepts.
- Validate Addresses: Ensure email addresses are valid to reduce bounces.
- Encourage Safelisting: Ask subscribers to add the new email address to their contact/safe list.
- Ramp Up Gradually: Gradually increase sending volume to build reputation.
Expert view
Expert from Word to the Wise explains if you're starting from a new IP address, you'll likely have reputation issues, which can cause delays. Work on warming up the IP address properly before sending large volumes of mail.
29 May 2025 - Word to the Wise
Expert view
Expert from Email Geeks agrees with the approach of limiting email volume, ensuring email address validation, and asking subscribers to add the new email address to their contact/safe list.
8 Nov 2023 - Email Geeks
What the documentation says
4 technical articles
Gmail email delays post-SFMC migration are often tied to sender reputation and IP warming. Google Postmaster Tools can be used to monitor sender reputation, spam rates, and diagnose root causes of delays. Salesforce documentation stresses gradual IP warming for establishing trust with ISPs like Gmail, advising against rapid volume increases. RFC details that SMTP deferrals, triggered by spam filters and reputation systems, are temporary delivery failures which, if persistent, indicate fundamental problems. DKIM authentication ensures email legitimacy and prevents sender address forgery, impacting trust and deliverability.
Key findings
- Postmaster Tools: Google Postmaster Tools helps monitor sender reputation, spam rates, and diagnose email delay issues.
- IP Warming Importance: Gradual IP warming during SFMC migration is crucial for building trust with ISPs like Gmail.
- SMTP Deferrals: SMTP deferrals indicate temporary delivery failures due to spam filters or reputation systems; persistent deferrals suggest underlying issues.
- DKIM Authentication: DKIM authentication verifies email legitimacy and prevents sender address forgery, impacting trust and deliverability.
Key considerations
- Monitor Postmaster Tools: Actively monitor Google Postmaster Tools to identify and address sender reputation and spam issues.
- Phased IP Warming: Implement a phased approach to gradually increase sending volume during SFMC migration.
- Address Persistent Deferrals: Investigate and resolve root causes of persistent SMTP deferrals.
- Implement DKIM: Ensure DKIM is correctly implemented to authenticate emails and improve deliverability.
Technical article
Documentation from Salesforce explains that when migrating to SFMC with a new IP, gradual IP warming is critical to establish trust with ISPs like Gmail. Sending too much volume too quickly can trigger delays and spam filtering. The documentation outlines a phased approach to gradually increase sending volume.
25 Apr 2024 - Salesforce Help
Technical article
Documentation from Google details that Postmaster Tools provides data on sender reputation, spam rates, and other metrics. Monitoring these metrics can help identify issues causing delays and diagnose the root cause, such as spam complaints or authentication problems.
8 Apr 2022 - Google
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