We are still waiting for resolution on this issue. Microsoft has now indicated an update should be available within 48 hours, however we are still working through all channels to expedite resolution to this issue.
If your organization uses Microsoft 365, opening a support ticket from your own tenant may help escalate and resolve the issue for deliverability to your own domain. When doing so, reference the Trackops sending IP address, the notifications email address you receive email from, the error code you're receiving (5.7.511), and any additional relevant information.
For emails sent to Microsoft customers that are failing, re-sending email outside of the system (or forwarding system emails) may provide better outcomes until this issue is resolved.
We will continue to post updates until this issue is resolved. Thank you again for your continued patience and support.
Posted Aug 15, 2026 - 23:41 MDT
Update
We are continuing to work with upstream engineering and Microsoft to resolve this issue. Unfortunately mitigation is taking longer than we’d like, but we are maintaining dialog with upstream while this issue is resolved.
Posted Aug 15, 2026 - 16:08 MDT
Update
We have received confirmation from Microsoft that their Escalations Team is working to resolve the issue with an urgent priority. We continuing to work with their team to get this issue resolved as soon as possible.
Posted Aug 15, 2026 - 08:40 MDT
Update
Email to Microsoft 365 systems is still impacted with a high failure rate. We are still working to resolve this issue.
Posted Aug 15, 2026 - 06:27 MDT
Update
We are continuing to work on a fix for this issue.
Posted Aug 15, 2026 - 00:49 MDT
Identified
We are still working through Microsoft channels to resolve this issue. Updates to follow.
Posted Aug 14, 2026 - 22:02 MDT
Update
We are still working with Microsoft to determine the cause of this issue. Emails to public Microsoft accounts (Outlook) are not affected, however 365 and Exchange accounts are seeing high failure rates.
Email to all other systems is operating normally.
We will continue to provide updates.
Posted Aug 14, 2026 - 18:54 MDT
Investigating
We are currently seeing a large number of blocked/dropped messages to Microsoft based email services. We are looking into the situation.