Cannot able to Connect the Sharepoint Online Site using CSOM

Target Environment : SharePoint Online

Coding Technique : Csom

Hi All,

I am facing the challenge with connecting to a sharepoint online site using csom. We are having 2 way authentication to connecting a site.

Example:

If https://csharpcorner.microsoft.com is a Online Site while loading we have to [email protected] & followed by the next below window with domain name.

username : domain\username

Password : ******************

because of this i couldn't able to connect a site with my code.

Code

string userName = textBox1.Text;

string password = textBox2.Text;

SecureString SecurePassword = GetSecureString(password);

clientContext.Credentials = new SharePointOnlineCredentials(userName,SecurePassword);

Web web = clientContext.Web;

clientContext.Load(web);

ServicePointManager.SecurityProtocol |= SecurityProtocolType.Tls12;

clientContext.ExecuteQuery();

I'm getting the below exception.

Error

Can anyone assist me on this issue asap.

Thanks

Raghav