Freshdesk Support Note

Subject: Fixing Office365 SMTP Email Sending Issues in SoEasy

Applies To:

  • Users using SwithMail or SoEasy to send emails via Office365 (Outlook)

  • Users encountering error 535 or 5.7.139: "Authentication unsuccessful"

Issue Summary:
Microsoft Office365 enforces modern authentication rules. Legacy applications (like SwithMail) may be blocked unless proper authentication is configured. This leads to errors when attempting to send email.

Error Message Example:

535 5.7.139 Authentication unsuccessful, the request did not meet the criteria to be authenticated successfully. The SMTP server requires a secure connection or the client was not authenticated.

Root Causes:

  • Multi-Factor Authentication (MFA) is enabled but not supported by basic SMTP login

  • SMTP AUTH is disabled for the user

  • TLS is not correctly configured in the client

Fix Options:

Option 1: Use an App Password (Recommended if MFA is enabled)

  1. Log in to https://portal.office.com with the user account.

  2. Go to "My Account" > "Security Info".

  3. Select "Add method" > Choose App Password.

  4. Generate the password and use it in the SoEasy email setup screen.

Note: This replaces your normal password in the configuration.

Option 2: Enable SMTP AUTH for the User

  1. Log in to https://admin.microsoft.com as an Office365 admin.

  2. Go to Users > Active Users.

  3. Select the email account (e.g., name@mycompany.xxx).

  4. Click Mail > Manage email apps.

  5. Ensure Authenticated SMTP is checked.

  6. Save changes.

SoEasy Email System Configuration:

  • SMTP Server: smtp.office365.com

  • Port: 587

  • Encryption: TLS

  • Email requires authentication: Yes

  • Username: full email address

  • Password: either standard password or App Password

Final Notes:

  • If MFA is off, a normal password may work (not recommended)

  • If errors persist, verify TLS is active and port 587 is not blocked by firewall

  • Document any changes made in the user’s profile

Support Contact: SIMBA
support@soeasy.co.nz