Your Microsoft 365 administrator needs to approve PlainMailOS

Many organizations only let employees connect apps that an IT administrator has approved. When that applies to you, Microsoft shows a message like “Need admin approval” while you connect your mailbox. Nothing is wrong with your account; an administrator just has to approve PlainMailOS once for your organization.

If you are the administrator

Either of these works:

1. From PlainMailOS: sign in as an organization owner or admin, open Settings → Company mailboxes, choose Start company-wide connect, then Microsoft 365. You'll be sent to Microsoft to approve PlainMailOS for your organization; you can then connect your colleagues' mailboxes or let each person connect their own.
2. From Microsoft: if your organization uses Microsoft's admin consent requests, open the Microsoft Entra admin center, go to Enterprise applications → Admin consent requests, and approve the request for PlainMailOS.

If you are not the administrator

Send this page to your IT team. Once they've approved PlainMailOS, connect your mailbox again from Mailboxes → Connect Outlook / Microsoft 365.

What PlainMailOS asks for

Permission to read mail in the connected mailboxes and keep access while you're signed out (so mail keeps syncing), plus your basic profile (name and email address). PlainMailOS only sends or changes mail when you choose an action that does so, or when your organization turns on an automation that does (off by default). See the privacy policy for how mail is handled.