Why are emails from one account going to spam while emails from another account are not, despite having similar configurations?

Email marketer from ActiveCampaign Blog shares that one account may have poor list hygiene practices. List hygiene includes, removing invalid email addresses, unsubscribes, bounced emails, and spam complaints.

Email marketer from Mailchimp Resource Center explains that variations in list quality, even with similar configurations, can lead to different outcomes. One list might have more engaged users than the other, resulting in better inbox placement.

Email marketer from SendGrid Blog suggests that large differences in sending volume can trigger spam filters. An account that suddenly increases its sending volume significantly might be flagged as a potential spammer.

Email marketer from Neil Patel's Blog shares that inconsistent spam filtering can occur if one account triggers spam filters more frequently due to variations in content, subject lines, or sending frequency, even if the overall configuration appears identical.

Email marketer from Campaign Monitor shares that if you’re sending email from a new IP address, you need to warm it up to establish a positive sending reputation. Warming your IP helps ISPs learn that your emails are wanted and that you’re a legitimate sender. If you don't do this then this could cause email to be filtered into the spam folder.

Email marketer from Reddit suggests that even if the sending domains and IP addresses are the same, different tracking domains can significantly impact deliverability. Spam filters might associate one tracking domain with poor sending practices from other users.

Marketer from Email Geeks recommends removing all URLs and sending a test email to see if it lands in the inbox. This helps determine if a URL is triggering the spam filter.

Marketer from Email Geeks recommends checking the sending IP address from messages in the spam folder and inbox to see if a particular IP from the pool of IPs is delivering messages to spam.

Marketer from Email Geeks recommends comparing email headers between emails that land in the inbox and those that go to spam, and looking for Gmail's spam notification for reasons why it was filtered.

Email marketer from Litmus Blog explains that different levels of user engagement (opens, clicks, replies) between the accounts will cause different levels of spam placement. Even if configurations are similar, low engagement signals can lead to increased spam filtering.

Email marketer from Email Marketing Forum speculates that the ESP might have internal reputation scores for each account. Even if the configurations look the same, the ESP could be prioritizing deliverability for one account over the other based on their internal metrics.

Email marketer from Email on Acid Blog shares that shared IP addresses may have different reputations. Even when accounts use the same pool of IP addresses, one account might be using IPs that have been previously associated with spam-like behavior.

Expert from Word to the Wise highlights the danger of testing deliverability solely with seed lists. Seed lists often lack the engagement history of real users, so an email might perform well on a seed list but poorly with actual subscribers due to factors like lack of prior interaction and differing spam filter responses.

Expert from Email Geeks suggests considering whether subscribers are actively subscribing to mail from one account and then being added to a different list. If subscribers don't expect mail from the second list and interact with it negatively, it can negatively impact the email's reputation.

Expert from Spam Resource shares that properly setting up feedback loops and maintaining good list hygiene helps manage your sender reputation and avoid the spam folder. Even with similar configurations, one account might lack active feedback loops and proper bounce/complaint handling, resulting in a worse reputation and increased spam filtering.

Documentation from Microsoft 365 documentation states that content filtering is a primary reason. Slight differences in email content, even if seemingly negligible, can cause different outcomes. For example, using certain keywords or having a different image-to-text ratio in one account can trigger spam filters.

Documentation from Google Postmaster Tools Help explains that sender reputation is a crucial factor. Even with similar configurations, one account might have a lower reputation due to past sending behavior, complaint rates, or engagement metrics, leading to spam filtering.

Documentation from Amazon Web Services explains that if one account has a weaker reputation of sending authorization records, then the reputation will be weaker. If authentication is set up correctly for both but one is newer than the other then that account is more likely to get placed in the spam folder.

Documentation from SparkPost Documentation highlights the importance of feedback loops. If one account isn't properly set up with feedback loops, they won't receive information about spam complaints, leading to a degraded sender reputation over time.

Documentation from RFC Editor details that subtle misconfigurations or differences in SPF, DKIM, or DMARC settings between the two accounts can result in one account being flagged as spam, even if the other isn't.