How to send mail from sql server 2016

Hi All

   I am setup mail configuration in sql server database but it is not send and return error. like below is error message.

The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 9 (2019-04-19T10:43:22). Exception Message: Cannot send mails to mail server. (The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at). )

Can you Please send some sample code .