Microsoft 365 Monitor

Last 30 minutes

Share of successful connections per endpoint (3 connections per run) and average time to the first response.

History

Each cell covers 15 minutes (24 hours) or one hour (7 days). Hover over or tap a cell to see the values.

• all connections successful
• partly successful
• no connection successful
• no measurement

Why connections fail

Failed connections in the selected period, by type of error.

Affected Microsoft server networks

The Exchange Online host names point to many servers. Each measurement goes to a randomly chosen address. The table groups the addresses into networks (/24) and shows whether some server groups are affected more than others.

How we measure

• Every 5 minutes the measuring server opens three connections to each endpoint, one after another: name resolution (DNS), TCP connection, TLS encryption and the server's first response (HTTP status or SMTP greeting).
• Successful means: the server answered each step within 10 seconds, for HTTP with a status below 500. No mailbox sign-in takes place.
• The measuring server is located in a data centre in Europe. Its internet exit changes location regularly; in the selected period measured via: ….
• Entra ID (sign-in) and Microsoft Graph run on separate infrastructure and serve as a comparison; the reference service (Cloudflare) checks the measuring server's own network.

Limits of the measurement

• This is a single measuring point. Other regions and networks may be affected differently.
• It measures reachability, not whether mailboxes, calendars or mail flow work in your tenant. Service health in the Microsoft 365 admin center remains authoritative for your tenant.
• The measurement is deliberately light (about 20 connections every 5 minutes) and puts no load on the services.