Why are Microsoft IPs blocking AWS SMTP servers?

Email marketer from SocketLabs explains that problems arise from using shared IPs as your IP reputation can be affected by the activities of other users sending from the same IPs. If those activities are associated with spam or other negative behaviors, all users sharing that IP can be impacted. SocketLabs recommends using a dedicated IP address or a reputable sending platform.

Email marketer from Email on Acid explains that deliverability issues stem from poor IP reputation. Because AWS is a service widely used by spammers, and it is simple to create new accounts for malicious use, Microsoft may block AWS IPs to protect users.

Email marketer from SendGrid answers that Shared IPs are the quickest and easiest way to begin sending emails. However, because your sending reputation is shared with other senders, you risk your deliverability being impacted by another sender’s poor sending behavior. Consider switching to a dedicated IP address for greater control.

Marketer from Email Geeks says to never send from AWS directly, and if you send via some other platform please please update the rDNS on your AWS host to use your brand/domain.

Email marketer from Stack Overflow shares that AWS IP ranges are known for being used for spam and other malicious activities, leading to poor reputation and blocking by services like Microsoft. They suggest using a dedicated IP address, warming it up properly, and following best practices for email sending.

Email marketer from SparkPost shares that negative IP reputation, especially on shared IPs, can lead to poor email deliverability. This happens when a sender engages in sending practices that are regarded as questionable, untrustworthy or unwanted. Microsoft may proactively block AWS IPs if they have negative reputations.

Email marketer from MXToolbox explains that IP reputation is crucial for email deliverability. If AWS IPs are frequently used by spammers, Microsoft is likely to block the entire range to protect its users. Monitoring IP reputation and addressing any issues promptly is essential.

Email marketer from Mailjet shares that IP reputation is one of the most important factors for email deliverability. Mailjet recommends avoiding shared IPs and warming up dedicated IPs.

Email marketer from Litmus answers that maintaining a good sending reputation involves sending mail that people want, authenticating email and avoiding spam traps. Poor practices can impact IP reputation, leading Microsoft to block AWS IPs.

Email marketer from Reddit responds that Microsoft likely blocks AWS IPs due to the high volume of spam originating from AWS. They recommend using a dedicated IP with a good reputation or using a reputable email service provider (ESP) instead of directly sending from AWS.

Expert from Email Geeks says you’re in a bad neighborhood and there’s not much you can do about that other than move.

Expert from Email Geeks explains that Microsoft pretty much hates AWS and a lot of folks go through this, and that the full IP space has a bad reputation. If someone nearby on your /24 (or sometimes larger range) sends spam, you’re going to get tarred with that brush.

Expert from Spam Resource responds that Microsoft may block AWS IPs because AWS provides infrastructure easily abused by spammers. Microsoft is not necessarily targetting AWS, just mitigating the impact of spam originating from their services.

Expert from Word to the Wise, Laura Atkins, responds that AWS has reputation problems stemming from its sign-up process, which makes it easy for spammers to get started sending. This results in large blocks, and a poor reputation.

Expert from Email Geeks says you should never, ever send mail from AWS. Ever.

Expert from Email Geeks explains that Microsoft has a very aggressive filter against all of AWS space

Expert from Word to the Wise, Laura Atkins, shares that cloud infrastructure platforms like AWS suffer deliverability issues due to spammers abusing the ability to set up and send bulk emails easily, affecting IP reputation and causing blocks.

Documentation from Microsoft explains that they block senders based on various factors, including IP reputation, spam complaints, and sending volume. If an AWS IP range is consistently sending unwanted email, Microsoft may block the entire range to protect its users from spam and phishing attempts.

Documentation from AWS notes that new AWS SES accounts have default sending limits and a limited IP reputation. Microsoft may automatically block emails from AWS if these factors are not properly managed, or are perceived as spam-like activity.

Documentation from AWS explains that shared IP addresses on AWS SES can be affected by the sending behavior of other users. If other users send spam, it can negatively impact the reputation of the shared IP, leading to blocking by email providers like Microsoft. Using dedicated IPs is recommended for greater control over reputation.

Documentation from Digital Ocean explains that Maintaining a good IP reputation is crucial for ensuring that your emails reach your intended recipients' inboxes. A poor IP reputation can lead to email blocking or filtering by email providers like Gmail, Yahoo, and Microsoft.