Why are my emails sent from Gmail SMTP ending up in spam folders in Outlook, Hotmail and Live?

Email marketer from Gmass explains that sending emails to old or unengaged email addresses will hurt sender reputation. Regularly cleaning the email list to remove disengaged contacts improves deliverability to Outlook, Hotmail and Live.

Email marketer from Mailjet explains that spam filters analyze email content for suspicious keywords and phrases. Using high-pressure sales language or deceptive subject lines can trigger these filters, causing emails sent from Gmail SMTP to land in spam folders of Outlook, Hotmail, and Live users.

Email marketer from Email Marketing Forum explains that low engagement rates (opens, clicks) signal to email providers that your emails are unwanted. Outlook, Hotmail, and Live may then filter your emails sent from Gmail SMTP to the spam folder based on engagement.

Marketer from Email Geeks shares they've been told the issue could be related to Microsoft disliking mail from Gmail's SMTP.

Email marketer from Sendinblue shares that if your emails aren't properly authenticated (SPF, DKIM, DMARC), they are more likely to be marked as spam by email providers like Outlook, Hotmail and Live.

Email marketer from Woodpecker shares that Gmail SMTP needs to have a warm up period by increasing the volume of emails slowly. Jumping straight into sending thousands of emails will appear as spam.

Email marketer from Neil Patel explains that a poor IP reputation can lead to emails landing in spam folders. If Gmail's IP has been used for spam, Outlook, Hotmail, and Live might block or filter emails originating from that IP.

Email marketer from Hunter shares that setting DMARC policies wrong, particularly the p=reject option, can lead to genuine emails being sent to spam.

Email marketer from Quickmail shares that your domain or IP address might be blacklisted by various organizations due to spam complaints or detection of spam-like activity. Being on a blacklist can cause emails sent from Gmail SMTP to automatically go to the spam folder in Outlook, Hotmail, and Live.

Email marketer from Reddit shares that Gmail's SMTP servers use shared IP addresses. If other users are sending spam, it can negatively impact the IP reputation and cause your emails to be flagged as spam by Outlook, Hotmail, and Live, even if your emails are legitimate.

Expert from Word to the Wise indicates that there are numerous possible reasons why email sent to Microsoft domains (Outlook, Hotmail, Live) gets blocked or filtered, ranging from IP reputation issues to content-related triggers, and the exact cause can be difficult to pinpoint without detailed investigation and working with Microsoft's sender support.

Expert from Email Geeks suggests trying to send email through an SMTP server that's not Gmail for a while to see if that helps, as the Hubspot -> Gmail integration might be the problem.

Expert from Email Geeks explains that most filters consider transactional mail bulk because it's basically the same message sent to a lot of people, with some minor levels of personalisation.

Expert from Word to the Wise shares that many deliverability problems stem from authentication issues (SPF, DKIM, DMARC) and incorrect configuration of sending infrastructure. Proper configuration and monitoring are critical to avoid spam filters and ensure messages reach the inbox.

Expert from Spam Resource explains that Microsoft is a particularly difficult receiver, and various factors such as content, list quality, and sender reputation influence deliverability. Even with proper authentication, Microsoft might still filter emails if they deem them unwanted.

Documentation from Microsoft explains that Outlook.com has specific policies and practices regarding email filtering. If your emails violate these policies (e.g., high complaint rates, spam-like content), they are likely to be delivered to the junk folder. This applies to emails sent from Gmail SMTP.

Documentation from Google Workspace Admin Help shares that exceeding Gmail's sending limits (number of recipients, daily sending limits) may cause emails to be throttled or marked as spam by recipient servers. Outlook, Hotmail and Live may view emails sent via Gmail SMTP in large volumes as potential spam.

Documentation from SparkPost explains that it's important to implement feedback loops to monitor spam complaints. High complaint rates from Outlook, Hotmail, and Live users can negatively impact your sender reputation, leading to your emails being directed to the spam folder.

Documentation from RFC highlights the technical specifications for SPF, DKIM, and DMARC. Properly implementing and configuring these authentication methods is crucial for ensuring that receiving mail servers (like Outlook, Hotmail, and Live) trust the origin of your emails sent from Gmail SMTP.