Email delivery issues

Microsoft has confirmed the cause: an anti-spam detection model in Exchange Online was incorrectly enforcing throttling against a subset of legitimate senders, including SuperOffice, causing "Server busy" delays for messages sent to and from external domains.

Microsoft is rolling back the affected model and adding impacted sending IPs to an allow list as an interim mitigation. They estimate this rollout will complete within the next 30 minutes (as of their last update at 2:26 PM GMT+2), with...

We've identified the cause:
this is a confirmed issue on Microsoft's side affecting delivery to Microsoft 365 / Outlook.com mailboxes, tracked internally by Microsoft as incident EX1467029. We've verified it affects multiple independent SuperOffice email systems (login/confirmation codes and Service/CRM emails) in the same way, confirming the cause is on Microsoft's end, not ours.

Affected emails are delayed, not lost, and will be delivered automatically once Microsoft resolves EX1467029. N...

We are continuing to monitor the scope of this issue.

We're aware of delays affecting emails sent from SuperOffice - including login confirmation codes, account activation links, password reset emails, and CRM mailings - to recipients whose email is hosted on Microsoft 365 or Outlook.com (Outlook, Hotmail, Live addresses).

This is caused by a known issue on Microsoft's side that is temporarily limiting how quickly they accept incoming mail from external senders, including us. It is affecting many senders across the internet, not just SuperOffic...