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

Question

0.00/5 (No votes)

See more:

using (MailMessage mm = new MailMessage("my email", txtEmail.Text))
{
mm.Subject = "تفيل الحساب";
string body = "مرحبا ";

mm.Body = body;
mm.IsBodyHtml = true;
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
//smtp.Host = "smtp.gmail.com";

smtp.UseDefaultCredentials = false;
NetworkCredential NetworkCred = new NetworkCredential("my email ", "<my password="">");

smtp.Credentials = NetworkCred;
smtp.EnableSsl = true;
smtp.Port = 587;// 465;
smtp.Send(mm);
}

Posted 2-Feb-15 7:45am

ddtrko

Add a Solution

4 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Afzaal Ahmad Zeeshan · Answer 1 · 2015-02-02T08:19:00

This problem is just with the network credentials you're passing alongwith the MailMessage object, first thing to check is whether your credentials (username and password combination) are correct as per server you're using; the username and password is correct for the Gmail server.

There are some past questions that you might be interested in reading to learn more on this problem, and you will finding interesting that all of them have the same problem, that include, Ssl to be enabled, username/password combination to be correct, or the port number to be correct.

Sending email using Gmail[^]
Smtp mail throuws an error[^]

Chances are you will find a perfect conclusion to this problem from these answers. Anyways, I would to suggest one more thing to you, to test before going further to read these answers. Which is to change the port to 25; if you're sure that the username/password combination is correct.

Member 11166005 · Answer 2 · 2015-02-02T22:50:00

this code helps u.i this so.don't forget to change email-id and password .check it out.textBox1.Text for emailID and textBox2.Text for password

MailMessage message = new MailMessage();
SmtpClient smtpClient = new SmtpClient();
string from = "YOUR MAIL-ID";
string msg = string.Empty;
try
{
MailAddress fromAddress = new MailAddress(from);
message.From = fromAddress;
message.To.Add(textBox1.Text);
message.Subject = textBox2.Text;
message.IsBodyHtml = true;

message.Body = richTextBox1.Text;
smtpClient.Port = 587;
smtpClient.Host = "smtp.gmail.com";
smtpClient.UseDefaultCredentials = true;
smtpClient.Credentials = new System.Net.NetworkCredential("YOUR MAILID", " YOUR PASSWORD");
smtpClient.EnableSsl = true;
smtpClient.Send(message);
message.Dispose();
MessageBox.Show("Email Send Successfully ....");
}

catch (Exception ex)
{

MessageBox.Show(ex.Message);
}

RajeeshMenoth · Answer 3 · 2015-02-02T23:31:00

Hai,

Can u refer this link..

a) go to gmail security center via this link blow or google search for “gmail secrity” and login with your gmail account
click here

b)next to “security” / “Recent activity” , click to “view all events”

c)You will able to see “Unusual Activity” , it will show all unusual activity events, select related event and approval it via click ” Yes, That was me!”

d)https://accounts.google.com/DisplayUnlockCaptcha[^]//Click allow access to your Google account

e)You have to enable login from other timezone / ip for your google account.

f)go to security settings at the followig link https://www.google.com/settings/security/lesssecureapps[^] and enable less secure apps . So that you will be able to login from all apps.

Lucifier Rocks · Answer 4 · 2015-02-02T17:45:00

Solution 2

Creditentials used are incorrect, please check and enter the correct credentials

Posted 2-Feb-15 17:45pm

Lucifier Rocks

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

4 solutions

Solution 1

Solution 3

Solution 4

Solution 2

Add your solution here

Preview 0