SMTP Server Requires a Secure Connection

Which link are you pointing out ?

When using email providers such as Gmail or eBay,etc, authentication occurs behind the scenes through protocols like SMTP and network credentials. When setting up an email server for sending emails, authentication configuration is necessary as it enables the sender to be verified and authorized to send messages to the recipient. Without authentication, sending emails to a recipient would not be possible. There are certain configuration required like SMTP Host, port number, etc

When you send an email, it is sent from your email account to the recipient's email account using the SMTP protocol. You can refer one my article for basic details - https://www.c-sharpcorner.com/UploadFile/2a6dc5/how-to-send-a-email-using-Asp-Net-C-Sharp/

A similar kind of configuration is in the server as well, still, if you are facing the same issue then you need to contact your respective server admin. For E.g Goddady has its own setup.

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

What can i do ?

Which error you are talking about ? This blog is the solution of server response was: 5.5.1 Authentication Required. Could you please describe your error ?

priyanka tandel This blog is the solution of server response was: 5.5.1 Authentication Required. But your error is different and it clearly mention 5.7.14.

Thank You Saritha :)