Is anyone else having trouble with Outlook or Exchange Online today? Some users here are seeing delayed or failed email, authentication errors, inaccessible webmail, and freezing when using shared mailboxes. The impact seems inconsistent across tenants and regions, so I'm trying to determine whether this is a broader service outage.
4 Answers
Webmail is unavailable for some of our users, but the desktop client still works for others. There have also been reports of related connection problems in other Microsoft 365 services, so the safest assumption is that this is a provider-side incident rather than an Outlook configuration issue.
We’re seeing the same thing. Some messages are delayed or failing with POISONMESSAGE, while other users can send normally. A few people can’t access webmail at all, and Outlook may freeze when shared mailboxes are involved.
Yes, Microsoft has an active Exchange Online incident, EX1464935. Reported symptoms include delayed or failed messages, authentication problems, trouble accessing the web interface or administration tools, and intermittent mailbox failures. The impact appears to vary by tenant and user.
It isn’t affecting everyone equally. Some organizations and regions are still working normally, while others are completely down. We’ve seen the issue across multiple locations, so it doesn’t look like a local client problem.

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