If several staff suddenly cannot use the same Microsoft 365 function, check service health before rebuilding profiles or reinstalling computers. The useful question is whether a known incident matches your symptom, service and time period—not merely whether a status page contains a warning.

Record the affected app, the action that fails, the first observed time and which users are affected. Compare a browser session with the normal desktop app when practical. Preserve the exact error without including private message contents or credentials.

Read the relevant incident

An authorised administrator can open the Microsoft 365 admin center and go to Health, Service health. Supported roles include Service Support admin and Helpdesk admin; a staff member without access can ask the organisation’s administrator to check.

Open the issue details and compare its affected services, user impact, estimated start time, latest update and status with your observations. Record the incident ID if it appears relevant. A Teams incident does not automatically explain an unrelated Excel-file problem.

If the administrator cannot sign in, Microsoft points to its public service-status page for known sign-in issues. That fallback is useful, but it should not be treated as a complete account-specific diagnosis.

Keep local evidence and service evidence separate

If the symptoms match, use any applicable official workaround and arrange a sensible recheck. Avoid making several disruptive local changes while the underlying service is being restored. Record which work remains blocked so colleagues can use an agreed temporary process.

If nothing matches, continue the local or account investigation. A healthy dashboard does not prove that your particular problem is imaginary or that every possible incident is already listed. The administrator can report an issue through the service-health page when appropriate.

After Microsoft marks a relevant incident resolved, repeat the original failing task on an affected account. Report the business function as recovered only after that check succeeds; a provider status change and a successful customer workflow are different pieces of evidence.

References: Microsoft 365 service health.