Using Outlook for iOS for personal email and calendar management
Hey there! Nice to meet you!
Unfortunately, there is a service alert on the server regarding sign‑in issues: https://status.cloud.microsoft/m365/referrer=serviceStatusRedirect
Kindly try the Microsoft Sign‑in Helper troubleshooter in case this works: https://support.microsoft.com/account-billing/microsoft-account-sign-in-helper-7117cc8d-0d68-4658-b4fb-c4b7ee8a8e28
If the issue persists, I'm afraid your only option is to wait for Microsoft to fix this, and please check the server status from time to time.
Thank you for your understanding.
Best regards,
Darhyl