I have to send mails using my web application. Given the below code showing The SMTP server requires a secure connection or the client was not authenticated. The server response was:
5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM.
Help me to find a proper solution. Thank you.
Code:
protected void btnsubmit_Click(object sender, EventArgs e)
{
Ticket_MailTableAdapters.tbl_TicketTableAdapter tc;
tc = new Ticket_MailTableAdapters.tbl_TicketTableAdapter();
DataTable dt = new DataTable();
dt = tc.GetEmail(dpl_cate.SelectedValue);
foreach (DataRow row in dt.Rows)
{
string eml = (row["Emp_Email"].ToString());
var fromAddress = "emailAddress";
var toAddress = eml;
const string fromPassword = "*****";
string body = "Welcome..";
// smtp settings
var smtp = new System.Net.Mail.SmtpClient();
{
smtp.Host = "smtp.office365.com";
smtp.Port = 587;
smtp.EnableSsl = true;
smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
smtp.UseDefaultCredentials = false;
smtp.Timeout = 600000;
}
// Passing values to smtp object
smtp.Send(fromAddress, toAddress, subject, body);
}
}
}
#Reshma- In case you have not figured it yet, here are below things that I tried and it solved the same issue.
Make sure that NetworkCredentials you set are correct. For example in my case since it was office SMTP, user id had to be used in the NetworkCredential along with domain name and not actual email id.
You need to set "UseDefaultCredentials" to false first and then set Credentials. If you set "UseDefaultCredentials" after that it resets the NetworkCredential to null.
Hope it helps.
You seem to be passing the From address as emailAddress, which is not a proper email address. For Office365 the From needs to be a real address on the Office365 system.
You can validate that if you hardcode your email address as the From and your Office 365 password.
Don't leave it there though of course.
I spent way too much time on this and the solution was super simple.
I had to use my "MX" as the host and port 25.
var sClient = new SmtpClient("domain-com.mail.protection.outlook.com");
var message = new MailMessage();
sClient.Port = 25;
sClient.EnableSsl = true;
sClient.Credentials = new NetworkCredential("user", "password");
sClient.UseDefaultCredentials = false;
message.Body = "Test";
message.From = new MailAddress("test#test.com");
message.Subject = "Test";
message.CC.Add(new MailAddress("dude#good.com"));
sClient.Send(message);
I use to have the same problem.
Add the domain solved it..
mySmtpClient.Credentials = New System.Net.NetworkCredential("email#domain.com", "password", "domain.com")
In my case, 2 Factor Authentication was turned on for the FROM account in Office 365. Once that was turned off, the email sent successfully.
Main two reasons only as mentioned in above comments
NetworkCredentials you set should be correct. Verify with try actually signing into the account.
You need to set UseDefaultCredentials to false first and then set Credentials
Or
Put smtp.UseDefaultCredentials = false; above the smtp.Credentials assignment.
In my case, I followed the following 3 steps and it worked.
If you are getting one of the following errors:
535 5.7.3 Authentication unsuccessful
5.7.57 Client not authenticated to send mail
There are a few things you should check:
Enable Client SMTP submission on the licensed mailbox being used:
From Microsoft 365 Admin Center, go to Active Users and select the user.
Go to the Mail tab.
In the Email apps section, select Manage email apps.
Verify that the Authenticated SMTP setting is checked (enabled).
Select Save changes.
Disable Multi-Factor Authentication (MFA) on the licensed mailbox being used:
In the Microsoft 365 admin center, in the left navigation menu, choose Users > Active users.
On the Active user's page, choose Multi-Factor Authentication.
On the Multi-Factor Authentication page, select the user and disable the Multi-Factor Authentication status.
Disable the Azure Security Defaults by toggling the Enable Security Defaults to No:
Sign in to the Azure portal as a Security administrator, Conditional Access administrator, or Global administrator.
Browse to Azure Active Directory > Properties.
Select Manage security defaults.
Set the Enable security defaults to toggle to No.
Select Save.
Microsoft Reference Link
This is an old question but since this is the first result in google for this error, I thought I would update my progress in this issue.
I spent way too may hours on this issue. In the end I had to change my Office 365 account's password few times until my code succeeded in sending emails.
Didn't have to make any changes in code.
If you are using office 365 follow this steps:
check the password expiration time using Azure power shell :Get-MsolUser -All | select DisplayName, LastPasswordChangeTimeStamp
Change the password using a new password (not the old one). You can eventually go back to the old password but you need to change it twice.
Hope it helps!
Probably the password of the account that you trying to send e-mail is expired. Just check your password policy expire date.
In my case I was using the MailMessage constructor that takes two strings (to, from) and getting the same error. When I used the default constructor and then added a MailAddress object to the To property of the MailMessage it worked fine.
If you reorder your code this way, it should work:
SmtpClient client = new SmtpClient();
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential(mailOut, pswMailOut);
client.Port = 587; // 25 587
client.Host = "smtp.office365.com";
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.EnableSsl = true;
MailMessage mail = new MailMessage();
mail.From = new MailAddress(mailOut, displayNameMailOut);
mail.To.Add(new MailAddress(mailOfTestDestine));
mail.Subject = "A special subject";
mail.Body = sb.ToString();
client.Send(mail);
I changed the Office365 password and then tried to send a test email and it worked like a charm for me.
I used the front end (database mail option) and settings as smtp.office365.com port number 587 and checked the secure connection option. use basic authentication and store the credentials. Hope this turns out useful for someone.
In my situation, our IT department made MFA mandatory for our domain. This means we can only use option 3 in this Microsoft article to send email. Option 3 involves setting up an SMTP relay using an Office365 Connector.
Try resetting your password for the email used. Had similar issue, and got it fixed only after changing password.
I had similar issue. please read this microsoft support article.
specially this section.
For us it failed this way but only from the servers (Azure) not from the developer machines.
It turned out that the Office365 admin required MFA when accessing office365 from outside of the corporate country.
Our production server was in Ireland but the dev machines where in Sweden -> confusion... The admin turned of MFA for our sending account -> works.
Started working after adding property:
mail.smtp.starttls.enable=true
Using:
mail.smtp.host=smtp.office365.com
mail.smtp.port=587
mail.transport.protocol=smtp
mail.smtp.auth=true
mail.smtp.starttls.enable=true
mail.smtp.user=xxx#example.com
mail.smtp.password=xxx
mail.smtp.from=yyy#example.com
Set the User default credentials to true:
smtp.UseDefaultCredentials = True;
Before that, input your credential:
smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
This should work fine.
I was new to SMTP client in C#. So I decided to test it with my credentials. I built an ASP.NET Web forms application that has a Contact Us page on which I am trying to send an email to whoever person fills the form.
I tried sample code after going through this article - https://www.c-sharpcorner.com/UploadFile/87b416/sending-a-simple-email-using-smtpclient-in-C-Sharp/
I have one account in Yahoo so I used its SMTP domain "smtp.mail.yahoo.com" with port number: 465, then my app always threw Timeout exception. So I decided to try with Google's server "smtp.gmail.com" with "587" port and now it raised different exception with message:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required
I don't understand what are the prerequisites for working with SMTP on secure servers like Google and Yahoo. Please someone explain.
Also note that I didn't have 2 step verification enabled for my Google account, just to make it clear since some questions on SO have mentioned that this might be the problem.
I also read this question but I am testing directly on my machine - Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required
In case if it helps, here is the sample code:
try
{
MailMessage m = new MailMessage();
m.From = new MailAddress("dummy123#gmail.com");
m.To.Add(new MailAddress("dummyreceiver123#gmail.com"));
m.Subject = TBSub.Text;
m.Body = TBBody.Text;
m.IsBodyHtml = true;
NetworkCredential nc = new NetworkCredential();
nc.UserName = "dummy123"
nc.Password = "dummy#123";
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.Credentials = nc;
smtp.EnableSsl = true;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Send(m);
}
catch (Exception ex)
{
//Log this error
}
I just tested out your code it works fine you just need to modify this section:
nc.UserName = "test"
nc.Password = "password";
This has to be a valid gmail or google app email along with the password for the smtp connection to work properly. I would recommend that you put in your own for testing purposes, and then modify this to have your email as well:
m.From = new MailAddress("yourEmail#gmail.com");
m.To.Add(new MailAddress("yourEmail#gmail.com"));
Just so that you can validate that your message is being passed from your function.
I'm working on an ASP.NET Web Forms app and I'm trying to programmatically send an email to myself. I'm using Gmail's SMTP client, and all is well except that when I send my message, I get this error:
"System.Net.Mail.SmtpException: 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"
If I go into my gmail account settings and enable an option that allows me to allow access for "less secure apps", everything works fine. I'm wondering how I can send my email with having this option enabled.
protected void sendEmail(object sender, EventArgs e)
{
var client = new SmtpClient("smtp.gmail.com", 587)
{
Credentials = new System.Net.NetworkCredential("myusername#gmail.com", "mypassword"),
DeliveryMethod = SmtpDeliveryMethod.Network,
EnableSsl = true
};
MailAddress from = new MailAddress("myusername#gmail.com", "Torchedmuffinz");
MailAddress to = new MailAddress("myusername#gmail.com", "Torchedmuffinz");
MailMessage message = new MailMessage(from, to);
message.Subject = "test";
message.Body = "test";
Attachment attachFile = new Attachment(#"pathtofile");
message.Attachments.Add(attachFile);
try { client.Send(message); }
catch (Exception email_exception)
{
System.Diagnostics.Debug.WriteLine(email_exception);
}
}
Gmail port 587 does not support SSL.
I think the following code should work for you.
MailMessage msg = new MailMessage();
msg.From=new MailAddress("yourmail#gmail.com");
msg.To.Add("receiver#receiverdomain.com");
msg.Subject="Your Subject";
msg.Body="Message content is going to be here";
msg.IsBodyHtml=false; //if you are going to send an html content, you have to make this true
SmtpClient client = new SmtpClient("smtp.gmail.com");
client.Port=587;
NetworkCredential credential=new NetworkCredential("yourmail#gmail.com","your gmail password");
client.UseDefaultCredentials=false;
client.Credentials=credential;
client.Send(msg);
There is a possibility to use Google SMTP servers without 'Allow less secure apps' option, but you cannot use your standard google username and password. See my instructions on other post:
Is there a way to use ASP.NET to send email through a Google Apps acccount without selecting the 'Allow less secure apps' option?
I have read other answers on the stackoverflow. but none of the solutions work for me.
I'm trying to send email through live.com, but unable to it.
The error message:
mailbox unavailable. The server response was: 5.7.3 requested action aborted;
user not authenticated
or error message:
System.Net.Mail.SmtpException: Service not available,
closing transmission channel.
The server response was: Cannot connect to SMTP server 65.55.176.126
(65.55.176.126:587), NB connect error 1460
The code:
MailMessage mail = new MailMessage();
mail.From = new MailAddress("email#live.com");
mail.To.Add("someone#someone.com");
mail.Subject = "hello";
mail.Body = "awefkljj kawefl";
mail.IsBodyHtml = false;
SmtpClient smtp = new SmtpClient("smtp.live.com", 587);
smtp.EnableSsl = true;
smtp.Credentials = new NetworkCredential("email#live.com", "password");
smtp.Send(mail);
Are you able to send the email by using above code?
It works before, last year, but it is no more working now.
I'm not sure what has been changed to live.com email server.
What new settings or parameters should apply?
I ran into an issue where I was unable to send emails using the smtp.live.com SMTP server from certain hosts -- particulary Azure hosts. In my case, the SMTP attempt was from a host that I had never used to sign-in previously, so the attempt was blocked with the 5.7.3 error:
Mailbox unavailable. The server response was: 5.7.3 requested action aborted; user not authenticated
The solution was to browse to the account settings, locate the SMTP request in its recent activity, and select "This was me":
Tested and it works (different host address and a few other property set):
using (var client = new SmtpClient("smtp-mail.outlook.com")
{
Port = 587,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
EnableSsl = true,
Credentials = new NetworkCredential(_sender, _password)
})
{
using (var mail = new MailMessage(_sender, _recipient)
{
Subject = _subject,
Body = _message
})
{
client.Send(mail);
}
}
Also, if the account has two-step verification turned on, you'll have to generate an app password and use that instead.
Your code works for me without any changes with a live.com address. I am able to generate the same exception by simply putting an incorrect password.
I would suggest following checks:
Did the user change password recently? Are you able to login with the credentials provided over the web interface?
if yes, does your program uses the exact same credentials? please note that white space can be your enemy.
I am sending mail using this code
using System.Net.Mail;
using System.Net.Security;
MailMessage mail = new MailMessage();
mail.From = new MailAddress("abc#gmail.com");
mail.To.Add("xyz#gmail.com");
mail.IsBodyHtml = true;
mail.Subject = "Email Sent";
mail.Body = "Mail Done";
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.Credentials = new System.Net.NetworkCredential("abc#gmail.com", "123456");
smtp.EnableSsl = true;
smtp.Send(mail);
Label1.Text = "Mail Sent";
Whem I am using abc#gmail.com(one email id) for sending email, mail will successfully send but when I am using pqr#gmail.com(another mail id) mail sending failed. On local server both "abc" & "pqr" working fine.
Please help me to sort out this problem.
Error Message
the smtp server requires a secure connection or the client is not authenticated the server response was 5.5.1 authentication requires
Update you code to the following:
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.Credentials = new System.Net.NetworkCredential("abc#gmail.com", "123456");
smtp.EnableSsl = true;
smtp.UseDefaultCredentials = false;
smtp.Send(mail);
Try this line after the enableSSl=true code
smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
Gmail has added a new security feature for not to allow sending email using the less secure apps. You have to change the settings for your gmail account to allow access by less secure apps using steps given by google at below link
https://support.google.com/a/answer/6260879?hl=en
Enable less secure apps to access accounts
1.Sign in to your Google Admin console.
Click Security > Basic settings.
Under Less secure apps, select Go to settings for less secure apps.
In the subwindow, select the Allow users to manage their access to less secure apps radio button.
Once you've set Allow users to manage their access to less secure apps to on, affected users within the selected group or Organizational Unit will be able to toggle access for less secure apps on or off themselves.