Why are my Hotmail emails failing due to connection limits and what can I do?

Email marketer from Mailfence Blog shares advice that maintaining good sender reputation involves authenticating emails with SPF, DKIM, and DMARC. They also advise maintaining clean lists and removing unengaged subscribers to avoid spam complaints.

Marketer from Email Geeks suggests finding the right number of connections by sending emails, adding some random wait time to spread them out. Reducing the spread until getting throttled again, then go back increasing the wait times a little. Monitor and tweak from there.

Marketer from Email Geeks shares old documentation suggesting a technical limit of 500 simultaneous connections and 50 messages per connection at Microsoft. However, he notes that Microsoft caps connections and throughput based on reputation and past volumes and suggests staying under 150 simultaneous connections.

Email marketer from Quora states that closely monitor Microsoft's SNDS (Smart Network Data Services) for feedback on your IP's reputation. They recommend addressing any identified issues promptly and adjusting sending practices accordingly.

Email marketer from Reddit suggests that reducing the sending rate and implementing retry mechanisms can help avoid connection limit errors. They also highlight the importance of monitoring bounce messages to identify and address issues promptly.

Email marketer from GMass Knowledge Base explains that problems with Hotmail often stem from exceeding sending limits or poor engagement. They recommend segmenting lists to send to the most engaged users first and gradually increase volume.

Email marketer from EmailDeliverabilityBlog explains that temporary throttling could be resolved with retries. Implement your MTA to automatically retry any temporarily throttled email

Marketer from Email Geeks explains that the issue is likely due to reputation, causing Microsoft to throttle traffic. They suggest signing up for the SNDS program for reputation insights and sending to high-tier inventory or previous openers on Microsoft to avoid throttling.

Email marketer from StackOverflow answers that implementing connection pooling and reusing existing connections can help reduce the number of new connections opened. They also recommend setting appropriate timeouts to prevent connections from being held open indefinitely.

Email marketer from EmailGeek Forum shares that these errors often relate to IP reputation and recommends using SNDS (Smart Network Data Services) to monitor your IP's reputation with Microsoft. Also suggested is warming up your IP gradually.

Expert from Word to the Wise shares insight that Microsoft's throttling is heavily influenced by sender reputation. He suggests focusing on improving engagement metrics, authenticating email, and closely monitoring SNDS data to identify and address any reputation issues.

Expert from Email Geeks explains that the user should lower the number of SMTP connections in their MTA, suggesting a reduction to <50 connections to start. She recommends pausing sending for 4-12 hours and then rebuilding reputation to open more connections later. She also mentions unpublished connection limits that can cause reputation problems.

Expert from Spam Resource explains that connection limits are often a way for ISPs to manage traffic and prevent abuse. They advise checking the specific error messages for clues, reducing the sending rate, and implementing proper queuing and retry mechanisms to handle temporary throttling.

Documentation from Postmark explains that using SPF and DKIM is the standard for email providers to know your email is actually from you, or someone who has permission to send on your behalf.

Documentation from RFC Editor defines standards for SMTP connection management, emphasizing the importance of closing connections properly and avoiding excessive simultaneous connections to prevent server overload and potential blacklisting.

Documentation from Microsoft Support explains that exceeding connection limits can lead to temporary blocks. They advise reducing the number of concurrent connections and ensuring proper connection management. Also recommends reviewing the service agreement for specifics on limits.

Documentation from Google Workspace explains that even though it is for Gmail deliverability, it is the industry standard to ensure that you send wanted mail and have an easy unsubscribe option.

Documentation from MXToolbox suggests using their diagnostic tools to check for blacklisting, DNS issues, and other configuration problems that may contribute to connection limit errors. Their platform allows to check IP and domain reputation.

Documentation from ReturnPath now Validity explains that implementing SPF, DKIM and DMARC helps establish that you are authorized to send email on behalf of your domain, reducing the likelihood of emails being flagged as spam or throttled. They also mention the Certified program for enhanced deliverability.