c# .net Adsense ADO.NET Linq Viruses/security asp.net MVC JQuery Angular-js Node-js SEO Java C++ SQL API Networking vb.net .Net Css JavaScript Generics c#.Net entity framework HTML Website host Website Construction Guide HTTP tutorial W3C tutorial Web Services JSON Psychology Ionic framework Angular ReactJS Python Computer Android
c# .net

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Authentication required

| | ASP-NET , CSharp

I got the following error while sending email using asp.net c#.  You should check the authentication correctly configured or not in Network Credential. If then it is proper it should be blocked by the yahoo server. 

Solution:

You need to login into your account,

Go to Account info-> Account Security->

Turn on “Allow apps that use less secure sing in”

OR

Click here: https://login.yahoo.com/account/security#other-apps

Turn on “Allow apps that use less secure sing in”