Microsoft 365 Has Changed the Rules for Configuring Business Email Accounts with POP

Microsoft 365 Has Changed the Rules for Configuring Business Email Accounts with POP

Yes — it’s not that Microsoft 365 Outlook has simply “stopped accepting POP3” arbitrarily. There have been real changes in the way Outlook and Microsoft 365 handle POP/IMAP access, especially affecting Microsoft accounts and Exchange Online mailboxes. Here’s what is currently happening and what options you have.

1. Microsoft is phasing out POP/IMAP for Microsoft 365 accounts

Modern authentication and security

Microsoft has been disabling basic authentication for security reasons — the method traditionally used by POP and IMAP connections. This means connections that rely on basic authentication are no longer accepted.

Modern Outlook (included with Microsoft 365) does not support POP or IMAP with modern authentication for Microsoft 365 or Outlook.com mailboxes.

In other words, although POP technically still exists, Outlook cannot use it to connect to Microsoft 365 or Exchange Online accounts because basic authentication is no longer permitted.

2. Why it seems like Outlook “no longer accepts POP”

POP for Microsoft accounts no longer works

If your email address is something like @outlook.com, @live.com, @hotmail.com, or a Microsoft 365 business account, trying to configure it as POP in Outlook will not work because Microsoft’s servers only accept modern authentication methods that traditional POP cannot use.

Even when POP3 is enabled in the account settings, Outlook may still reject the connection if the required authentication method is not supported.

POP and IMAP are being gradually deprecated

Many providers (including Gmail) are also reducing support for basic POP authentication for security reasons, reinforcing this broader industry shift in email systems.

3. Is there any way to use POP and avoid leaving emails on the server?

If your account is NOT Microsoft / Exchange

Yes. If your account belongs to an independent provider (for example, your own domain hosted by a web hosting provider), you can usually still configure it in Outlook using POP3 if the provider allows it.

In that case you can typically:

• Download emails to your client and remove them from the server
  • Choose how many days a copy should remain on the server (if the provider supports it)

This can be configured in the advanced account settings:

1. In Outlook go to File → Account Settings → Change → More Settings → Advanced
2. Look for the option “Leave a copy of messages on the server” and adjust it as needed.

Important: This option only appears if Outlook detects the account as a pure POP3 account, not as a Microsoft 365 or Exchange account.

If the account IS Microsoft / Exchange

You cannot force Outlook to use POP3 to keep messages offline.

The classic option “leave a copy on the server and delete later” does not apply because Outlook can no longer authenticate using POP3 with these accounts in modern versions.

4. What alternatives exist instead of POP?

Using Exchange / Outlook synchronization

This is the recommended method. Add the account using Outlook’s automatic configuration, which uses Exchange ActiveSync, MAPI, or other modern protocols.

Emails are not removed from the server; instead, they remain synchronized across devices, including folders, calendars, contacts, and other data.

Using another email client that supports OAuth2 with IMAP

Some email clients such as Thunderbird can connect using IMAP with modern authentication (OAuth2), depending on the email provider.

These clients can also be configured to download messages locally, although this depends on the provider’s authentication support.

Quick summary