How to configure MailKit without password - asp.net-core

Question

In ASP.NET Core 6 Web API, I am using MailKit for Email configuration. I am using the SMTP server of my company which doesn't need a password.
I have this:
public class MailSettings
{
public string SmtpServer { get; set; }
public string SenderName { get; set; }
public string SenderEmail { get; set; }
public int SmtpPort { get; set; }
}
Since I am using my company SMTP configuration that needs no password, I use this method to send mails:
public async Task<bool> SendEmailAsync(MailRequest mailRequest)
{
var email = new MimeMessage { Sender = MailboxAddress.Parse(_mailSettings.SenderEmail) };
email.To.Add(MailboxAddress.Parse(mailRequest.ToEmail));
email.Subject = mailRequest.Subject;
var builder = new BodyBuilder();
if (mailRequest.Attachments != null)
{
foreach (var file in mailRequest.Attachments.Where(file => file.Length > 0))
{
byte[] fileBytes;
await using (var ms = new MemoryStream())
{
file.CopyTo(ms);
fileBytes = ms.ToArray();
}
builder.Attachments.Add((file.FileName + Guid.NewGuid().ToString()), fileBytes, ContentType.Parse(file.ContentType));
}
}
builder.HtmlBody = mailRequest.Body;
email.Body = builder.ToMessageBody();
try
{
using var smtp = new SmtpClient();
smtp.Connect(_mailSettings.SmtpServer, _mailSettings.SmtpPort, SecureSocketOptions.StartTls);
smtp.Authenticate(_mailSettings.SenderEmail);
await smtp.SendAsync(email);
smtp.Disconnect(true);
return true;
}
catch (Exception e)
{
_logger.Error(e, e.Source, e.InnerException, e.Message, e.ToString());
return false;
}
}
I got this error:
Argument 1: cannot convert from 'string' to 'MailKit.Security.SaslMechanism'
and it highlights this line of code:
smtp.Authenticate(_mailSettings.SenderEmail);
Expecting me to do it this way:
smtp.Authenticate(_mailSettings.SenderEmail, _mailSettings.Password);
How do I resolve this without password?
Thanks