Authentication failed on Office 365 SMTP server

Neel Oza 0 Reputation points


Hope you are doing well.

We are experiencing the following error when using the Office 365 SMTP server (Nodejs Nodemailer) to deliver emails.

"Invalid login: 535 5.7.139 Authentication unsuccessful, user is locked by your organization's security defaults policy. Contact your administrator."

Request options: 

host: "",
  secure: false,
  port: 587,
  tls: {
    ciphers: "SSLv3",
    rejectUnauthorized: false,
  auth: {
    user: USER_EMAIL,

Best regards,


Microsoft 365
Microsoft 365
Formerly Office 365, is a line of subscription services offered by Microsoft which adds to and includes the Microsoft Office product line.
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