Why are Microsoft 365 emails being rate limited by Gmail and how can I fix it?

Email marketer from Gmass recommends segmenting your email lists to send more targeted and relevant content to subscribers. This can improve engagement rates and reduce the likelihood of being marked as spam, which can lead to rate limiting.

Email marketer from Email Geeks reinforces that the issue is likely due to a high volume of problematic emails sent via Office 365 and recommends proper email authentication with the sender's own domain when sending through them.

Email marketer from Mailjet recommends avoiding spam trigger words in your email subject lines and body content. Using such words can increase the likelihood of being flagged as spam, leading to rate limiting by Gmail.

Email marketer from Neil Patel's Blog emphasizes the importance of warming up your IP address when sending emails from a new domain or IP. This involves gradually increasing the volume of emails sent over time to establish a positive sending reputation with email providers like Gmail.

Email marketer from Reddit suggests verifying your SPF records to ensure they are correctly configured to include all authorized sending sources for your domain. Incorrect or incomplete SPF records can lead to authentication failures and increased rate limiting.

Email marketer from SendGrid Blog recommends proper email authentication practices such as SPF, DKIM, and DMARC. Implementing these measures helps verify the sender's identity and improves email deliverability, reducing the likelihood of being rate limited or marked as spam by Gmail.

Email marketer from Email on Acid advises regularly monitoring your sender reputation using tools like Google Postmaster Tools. This allows you to identify any issues with your sending practices and take corrective actions to improve deliverability.

Email marketer from Litmus suggests regularly cleaning your email lists to remove inactive or invalid email addresses. Sending emails to non-existent addresses can harm your sender reputation and increase the risk of rate limiting.

Email marketer from SparkPost highlights that Gmail considers engagement metrics, like open and click rates, when determining sender reputation. Improve these metrics by sending relevant and valuable content to keep your emails out of the spam folder and avoid rate limiting.

Email marketer from Mailtrap Blog shares that rate limiting often occurs because Gmail detects a sudden spike in email volume from a particular IP address or domain. This can be triggered by sending a large batch of emails without proper warm-up, or if the sending domain has a poor reputation.

Email marketer from Stack Overflow recommends implementing DKIM (DomainKeys Identified Mail) to digitally sign your outgoing emails. DKIM helps prove that the email was sent by an authorized sender and hasn't been tampered with, improving your sender reputation.

Expert from Spam Resource highlights the need for continuously monitoring your IP and domain reputation. Blacklisting can quickly lead to rate limiting issues, and proactive monitoring allows for swift corrective actions.

Expert from Email Geeks suggests that the Gmail rate limiting issue might be related to DKIM. Gmail might dislike the mail associated with the DKIM or SPF domain. Implementing DKIM as the sender's domain, not the default onmicrosoft.com domain, could help.

Expert from Email Geeks explains Gmail groups emails together based on the SPF domain or SPF hostname, which can cause issues when multiple clients use the same SPF domain without DKIM.

Expert from Word to the Wise advises senders to manage subscriber engagement effectively. This includes regularly removing unengaged subscribers and focusing on providing valuable content to those who are actively interested in receiving emails.

Expert from Spam Resource explains that rate limiting often stems from poor sending practices, such as sending large volumes of emails without proper authentication (SPF, DKIM, DMARC), and without list hygiene.

Expert from Email Geeks confirms that authenticating only via SPF and not DKIM could potentially cause the Gmail rate limiting issue. Furthermore, one of the most challenging issues Al Iverson dealt with was driven by SPF due to a lack of DKIM.

Documentation from RFC Editor explains SMTP rate limiting is a common practice to prevent abuse. SMTP servers often impose limits on the number of connections, messages, or recipients within a specific time frame. These limits are dynamically adjusted based on various factors.

Documentation from Google explains Gmail has specific guidelines for bulk email senders to ensure a positive user experience. Following these guidelines, including proper authentication, list management, and content quality, can help prevent rate limiting.

Documentation from Google Workspace Admin Help explains that Gmail implements rate limits to protect its users from spam and abuse. Exceeding these limits can result in temporary restrictions, which is indicated by error messages like '421 4.7.28'. These limits vary based on factors such as sender reputation and the type of email being sent.

Documentation from Microsoft Learn suggests that users experiencing rate limiting should review their sending limits and practices within Microsoft 365. It emphasizes the importance of adhering to Microsoft's service limitations and implementing best practices for sending email to external domains like Gmail.

Documentation from DMARC.org explains that DMARC (Domain-based Message Authentication, Reporting & Conformance) allows domain owners to specify how email receivers should handle messages that fail SPF and DKIM checks. Implementing DMARC can significantly improve email deliverability and reduce the risk of rate limiting.