The following suggestions should be followed to ensure smooth operation when interacting with Office 365's IMAP and SMTP servers.

email in Node Configuration

• "Chatty Client Policy": IMAP clients connecting to Microsoft 365 will get blocked for 15-30 minutes if there are lots of emails in the account. Trial and error testing has shown that checking for email once every ten minutes is a good compromise.

  Reference article: IMAP is not working correctly on Outlook Office365. Error: "User is authenticated but not connected"

  Set Refresh to 600 seconds or more.

email out Node Configuration

• Microsoft 365 SMTP server uses port 587 and is configured to use STARTTLS. The communication channel will automatically be upgraded to TLS based on Microsoft‘s STARTTLS server configuration.

  The Microsoft 365 SMTP server will generate one of the following errors if Use secure connection is enabled in the node.

  • "Error: Invalid login: 504 5.7.4 Unrecognized authentication type [{server}.outlook.com]"
  • "Error: 34403852288:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:/usr/src/crypto/openssl/ssl/record/ssl3_record.c:358
  Make sure to uncheck Use secure connection.