What causes Hotmail inbox placement issues during IP warming when switching ESPs?

Email marketer from Email on Acid explains that proper email authentication (SPF, DKIM, DMARC) is critical for inbox placement. Hotmail and other ISPs use these protocols to verify the sender's identity and prevent spoofing. Incorrect or missing authentication can lead to emails being filtered as spam.

Email marketer from Mailchimp shares that ensuring your email content isn't spammy is a key factor in email deliverability to all ISPs including hotmail. They suggest avoiding spam trigger words and phrases and using a reputable sending provider.

Email marketer from Neil Patel shares that poor list hygiene can negatively affect inbox placement at Hotmail. Sending to unengaged or invalid email addresses increases bounce rates and spam complaints, which can harm sender reputation and lead to inboxing issues.

Email marketer from Email Marketing Forum notes that sudden increases in email volume after switching ESPs can negatively impact Hotmail inbox placement. Gradual and consistent volume increases are recommended for optimal results.

Email marketer from Validity emphasizes the importance of monitoring sender reputation metrics, especially during and after switching ESPs. Analyzing bounce rates, spam complaints, and engagement data helps identify and address deliverability issues promptly, improving inbox placement at Hotmail.

Marketer from Email Geeks explains that using different IPs doesn't help much if the IPs are just ramping up. In cases where the IP has been seeing good performance for some time and then stops suddenly, and MSFT is unable/unwilling to help, then switching to a new IP has had some success.

Marketer from Email Geeks shares that sometimes tickets are lost, so making a new one can be reasonable. Some other times, MS will insist they can't do anything for a reason they can't say anything about, and the quickest way to solve the issue is to try other IPs as a last resort.

Email marketer from GlockApps explains that seed list testing can help identify Hotmail deliverability issues during IP warming. By sending test emails to various seed addresses, senders can monitor inbox placement and spam filtering, enabling them to make necessary adjustments to their sending practices.

Email marketer from Reddit shares their experience that Hotmail's spam filters are particularly sensitive to new IPs. They suggest starting with a very small, highly engaged segment and gradually increasing volume over several weeks to build a positive reputation.

Marketer from Email Geeks explains that ramping up at MSFT is almost always problematic, and has been the case for roughly a year. They note that MSFT does not like variations in volume and sending consistent volume every day during the ramp is more likely to stabilize numbers. They also share that requests for proactive accommodation have been largely ignored recently.

Marketer from Email Geeks responds that the new ESP should provide support. History matters with MSFT, so switching ESP might require extra effort, restrict target to more actives, and after best practices, open a ticket to MSFT if the ESP hasn't done so.

Expert from Word to the Wise explains that IP warming must be done properly, and not all IPs can be warmed at the same rate. Some IPs can only sustain low volumes of sending.

Expert from Spamresource shares that monitoring blocklists and deliverability testing are key to addressing email deliverability problems. Blocklists can be a large factor in inbox placement rates.

Documentation from Mailjet highlights that consistent sending volume and frequency impact email deliverability. Sudden changes in sending patterns, like those during or after switching ESPs, can trigger spam filters at ISPs like Hotmail. Gradual ramp-up is advised to maintain good inbox placement.

Documentation from Microsoft explains that sender reputation is crucial for inbox placement at Outlook.com. New IPs or those with low reputation may face placement in the junk folder until a positive reputation is established through consistent sending practices and positive user engagement.

Documentation from SparkPost explains that gradual IP warming is essential to build a sender reputation with ISPs like Microsoft. Starting with small volumes and gradually increasing over several weeks helps ISPs learn the sender's traffic patterns and assess their legitimacy, improving inbox placement over time.

Documentation from Google states to 'Send consistent volumes of mail. Avoid sending email bursts. Sending regular amounts of mail helps establish your reputation as a consistent sender.'