Microsoft delivery delays

Microsoft capacity is increasing and emails are beginning to deliver. However there remains 16+ hours of email queues that did not deliver giving double the rate to microsoft services than normal. This introduces new challenges on delivery due to standard rate limits microsoft has in inbound email that under normal circumstances are not exceeded.

Microsoft emails remain delayed.

Further information from microsoft can be followed at https://x.com/MSFT365Status/status/2120938282204688468

We have identified the Microsoft responses behind these delays, including “The maximum number of concurrent server connections has exceeded a limit, closing transmission channel” and “Temporary server error. Please try again later”, and added handling for them to our system.

Messages that receive these responses are now moved to a separate slow queue and retried automatically from there. This keeps them from backing up the main queue, so delivery to other destinations should no longer be held up behind Microsoft-bound mail.

Email to Microsoft-hosted recipients, including Outlook, Hotmail and Microsoft 365 domains, may continue to be delayed while the issue persists on Microsoft’s side. No mail has been lost, and no action is needed from senders. Delayed messages will be delivered as Microsoft accepts them.

Emails to Microsoft are currently delayed, with similar reports from other vendors on the Mail ops list including errors such as 'The maximum number of concurrent server connections has exceeded a limit, closing transmission channel'

The issue is widespread and causing email delays.