Outlook in Microsoft 365 on Windows 11 stopped working with POP3 July 16, 2026

Question

Running windows 11 Evaluation copy. Outlook stopped working with POP3 incoming server on July 16. This is the error message. "Log onto incoming mail server (POP3): The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).  The server responded: -ERR Cannot connect to POP server <PII removed>, connect error 10". I have talked with ISP and I am using the correct ports. They do not support third party clients (like Outlook) and have referred me to Microsoft.

Answer 1

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Hello,

I understand that Classic Outlook stopped receiving messages from the POP3 account, although the provider confirmed that the ports are correct.

Please note that this is a user-to-user forum, so contributors cannot access the provider’s POP server or account configuration. The message shows that Outlook cannot complete a connection to the specified POP server.

Please try the following:

1. Sign in to the provider’s webmail to confirm that the mailbox and password are still working.
2. Close Outlook, open Control Panel, search for Mail, and select Mail (Microsoft Outlook) > Email Accounts. Select the POP account, choose Change, and compare the following details with the provider’s documented settings:
   • Incoming POP server name
   • Incoming port
   • Encryption type
   • Username, usually the full email address
   • Whether Secure Password Authentication (SPA) is required
3. Select More Settings > Advanced, verify that the POP port and encryption option match each other, and then select OK > Test Account Settings. Change or update Outlook account settings
4. If two-step verification is enabled and the provider supports app passwords, create a new app password through the provider’s security page and enter it in Outlook instead of the regular password. This is one documented cause of the same interrupted-connection message on Windows 11. Outlook POP or IMAP server interrupted the connection

If the test still reports that it cannot connect to the POP server, please share the selected POP port and encryption type, without posting the email address or password.

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