Microsoft continue to work to resolve this incident. The most recent update from them is as follows:

Recovery efforts are ongoing across impacted infrastructure. We are
seeing early signs of stabilization, but service capacity has not yet returned
to normal levels and health remains variable as traffic is carefully
reintroduced.

Microsoft continue to work to resolve this incident. The most recent update from them is as follows:

We’re continuing to see increased server capacity stability after applying the upstream authentication/routing configuration component patch. With confirmation of server stability across the portions of infrastructure to which we've applied the patch, we’ve initiated its expansion systematically to focus on infrastructure supporting regions currently within or entering peak business hours. We’ll continue to monitor the status of changes applied and develop additional modifications intended to improve server stability and capacity.

As of now, we are not aware of any malicious activity that is causing this incident. We will continue to treat this incident with urgency and priority until full resolution. Once mitigated, we will provide full details of the root cause, defense-in-depth repair items, and more within a Post-Incident Report.

All basic Teams functionality appears to be working. Outlook, however, is experiencing downtime and is therefore inaccessible for all staff. Authentication appears to be unaffected by this outage.

Microsoft's most recent status update is:

We’re seeing positive results for server stability after applying an upstream authentication/routing configuration component patch to a portion of our infrastructure. We’ll continue to monitor its progress and are working to expand it to servers supporting active regions coming online.

We will provide further updates as soon as possible and apologise for any inconvenience caused.

Microsoft is experiencing a global outage. This may affect the availability of services, including (but not limited to) Outlook, Teams, Copilot, Forms & TOPdesk (Operator Section).

Microsoft are aware of the issue and are working on it as a matter of urgency. Please expect all services provided by Microsoft to be non-functional during this incident.

We will provide further updates as soon as possible and apologise for any inconvenience caused.