Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required

Question

I am using following code to send email. The Code works correctly in my local Machine. But on Production server i am getting the error message

var fromAddres         


        

Answer 1

I have faced the same problem. It happens when you turn on 2 Step Verification (MFA). Just Turn off 2 Step Verification and your problem should be solved.