Check your Microsoft 365 tenant
Go to Health → Service health in the Microsoft 365 admin centre. The tenant is your organisation’s Microsoft 365 environment. Check EX1550543 for Exchange Online and MO1550821 for the broader incident. If sign-in is unavailable, use Microsoft’s public status page.
The ABC reported Microsoft was investigating Exchange Online issues. Record what your own tenant shows, with AEDT, AEST, AWST or the applicable time zone on each timestamp.
Recover delayed email and keep working
Try Outlook on the web, test send and receive with an external address, and check shared mailboxes, the Outbox and nondelivery reports. Your administrator can run a message trace with sender, recipient, time and message ID.
Use a separate phone, messaging or CRM login for time-sensitive work. If mail still fails after recovery, open a support case with examples and timestamps.
Open a case with your supplier
If Microsoft bills you directly, open Help & support in the admin centre and ask for an Exchange Online SLA service credit. If an Australian CSP bills you, start with that reseller and ask it to escalate through its distributor where needed.
Microsoft allows the submitting CSP one month after the end of the affected billing month for Microsoft 365. Ask for your reseller’s deadline and written case number. For direct purchases, check the applicable contract.
Microsoft partner and reseller lookup · Check your invoice first, then confirm who supplies the licence in the admin centre. Use your reseller’s contractual support channel and ask for the deadline in writing.
What to include in the claim
Add your tenant ID (the GUID in the Microsoft Entra admin centre Overview), incident ID, affected workload, plan and billing details.
Record start and end times with zone, licensed and affected user counts and locations, Outlook on the web errors and message traces. Keep lost sales and staff costs separately when reviewing your contract or insurance.
Exchange Online credit thresholds
The standard Exchange Online webmail SLA measures qualifying user-minutes. The credit is 25% below 99.9%, 50% below 99% and 100% below 95% of monthly uptime on eligible fees.
Six hours for all users in a 30-day month means about 99.17%. The same downtime for one in ten users is about 99.92%. Email delivery delay is assessed under separate metrics.
Alternatives and continuity
Test Google Workspace, Zoho Workplace or Proton for Business with real shared inboxes, calendars, mobile devices, retention and complex Excel files.
If keeping Exchange Online, test an independently hosted continuity service with separate sign-in. For a migration, prepare MX, SPF, DKIM and DMARC changes and rollback.