Login issues - Not Found Error

Problem

404 Not Found

This error may appear due to following reasons

Note: Office 365 Business licenses don’t include Exchange.

• Invalid credentials.
• The admin account doesn’t have the sufficient permissions to login to the target server
• Mailbox Email address is not the Primary SMTP address
  
  

  The primary SMTP address must be specified when referencing a mailbox.

• Wrong license.

Solution

• Check the credentials by logging into the OWA.
• Try to log in to the target mailbox with the admin credentials.
• Ensure that the email address specified is the primary SMTP address for the end user.
• If admin credentials are used ensure that the SMTPS has sufficient rights.
• Check the authentication settings.