Why is Hotmail rate limiting my transactional emails due to IP reputation?

Email marketer from Reddit shares that throttling by Hotmail can occur even with transactional email if your sending patterns look suspicious (e.g., large volumes to new recipients). Monitor feedback loops and adjust sending practices accordingly.

Email marketer from Neil Patel shares that consistently sending high-quality emails, authenticating your emails with SPF, DKIM, and DMARC, and actively managing your email list (removing inactive subscribers) are key strategies to improve IP reputation.

Marketer from Email Geeks asks if the volume has increased suddenly recently.

Marketer from Email Geeks suggests that if these emails are coming from web form submissions to make sure the web forms are protected by captcha, else they could be getting flooded.

Email marketer from Mailjet shares that poor list hygiene (sending to inactive or invalid email addresses) is a major contributor to poor IP reputation. Regularly cleaning your email list is crucial.

Email marketer from SendGrid explains that sudden spikes in email volume can negatively impact IP reputation. They recommend gradually increasing sending volume over time and warming up new IPs before sending large campaigns.

Marketer from Email Geeks explains that it means that Hotmail doesn’t like the IP reputation and suggests following through and filling out the form they linked to.

Email marketer from GlockApps recommends that you should monitor your IP reputation using tools like Sender Score and ensure your emails aren't triggering spam traps, which can severely damage your reputation and lead to rate limiting.

Email marketer from Litmus shares that implementing DMARC is a key strategy for sender authentication, preventing spoofing, and ensuring that receiving mail servers trust your emails. A DMARC policy allows you to tell recipient servers what to do with messages that fail authentication checks.

Email marketer from Email on Acid explains that setting up feedback loops (FBLs) with ISPs like Hotmail allows you to identify and remove subscribers who are marking your emails as spam, which directly improves your sender reputation.

Email marketer from a Webmaster Forum shares 'Hotmail is very sensitive to sender reputation these days. Make sure you're following best practices, including authenticating your emails, using a dedicated IP address, and warming up that IP address before sending large volumes.'

Email marketer from Stack Overflow responds to a similar question with 'Ensure your mail server's reverse DNS is properly configured and matches the hostname. Check the IP against blacklists. Ensure SPF and DKIM records are correctly configured and valid.'

Expert from Spam Resource explains that Hotmail, like other ISPs, uses IP reputation to filter spam, even for transactional emails. If your IP has a history of sending spam or is listed on blocklists, it may be rate-limited or blocked.

Expert from Email Geeks shares that the mailstream has a poor reputation with recipients so it’s being throttled.

Expert from Word to the Wise responds that the major mailbox providers use engagement to determine the reputation of the messages. Laura recommends sending to only users who want to receive your mail.

Expert from Email Geeks explains that authentication is entirely unrelated and transactional mail doesn’t necessarily have a good reputation with recipients.

Documentation from Microsoft Support explains that Outlook.com uses reputation to help protect customers from spam. Poor IP reputation can lead to rate limiting or blocking.

Documentation from RFC Editor explains that 4xx SMTP codes are temporary errors, and a 451 error specifically suggests a temporary problem on the server side, often related to resource availability or policy restrictions like rate limiting.

Documentation from SparkPost explains that using a dedicated IP address for sending email gives you control over your sender reputation, as your sending practices won't be affected by other users on a shared IP.

Documentation from Google explains that while it refers to bulk email, many of the same principles around authentication, list management and spam complaints are equally applicable to transactional email. They recommend that you follow their best practices for sending emails, including setting up SPF, DKIM and DMARC.