US SMTP server blacklisted by Microsoft Friday 24th January 2020 15:36:00


Our US SMTP service is currently on Microsoft's blacklist. Messages sent to email addresses that use Microsoft's email services (including hotmail.com and outlook.com) may be bounced back to their original sender.

We're working with MS to have the server de-listed and will update this incident when it is done.

Microsoft has once again assured us that our US SMTP has been removed from their blacklist. We'll continue to monitor.

We are still seeing ban activity In spite of the assurance from Microsoft that our US SMTP was removed from their blacklist. We'll continue to work with them to get this resolved.

Microsoft has delisted our US SMTP as of approximately 2:15 PM UTC 31 Jan 2020. It may take another couple of hours for the delisting to take full effect, so we will continue to monitor.

This issue is ongoing. We've taken all of the required actions as dictated by Microsoft so far and are waiting for them to delist the server.

In the meantime if you are a US customer affected by this block, feel free to use our German SMTP server to send mail: smtp.de.opalstack.com