5.7.57 SMTP - Client was not authenticated to send anonymous mail during MAIL FROM error

Question

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);
     }
  } 
 }

Did you anonymize this, or are you actually trying to send over office.com with that login? — fk2, May 20 '15 at 07:48
I've been ableto send an email with the SMTP config shown, but I moved smtp.UseDefaultCredentials = false; before smtp.Credentials = ... as Kiquenet write below — Raphael, Jun 19 '19 at 15:49

score 45 · Answer 1 · edited Jul 08 '15 at 10:25

45

@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.

edited Jul 08 '15 at 10:25

Nikolay Kostov

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answered Jul 08 '15 at 10:19

Navneet

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That's it! I didn't know "UseDefaultCredentials" clears the Credentials. Thanks! – nwestfall Jul 21 '16 at 20:03
1

In my case, it doesn't matter which one goes first. As long as the "UseDefaultCredentials" is false. It works. I wonder why. – Weihui Guo Oct 31 '18 at 11:57
1

In my case, someone has accidentally turned MFA on in some cases (but not most). You can go to this page using the email account to see if MFA is enabled in these cases (also triggers when trying to send email): https://mysignins.microsoft.com/security-info – hamboy Jul 20 '23 at 02:34

score 38 · Accepted Answer · edited Jun 20 '20 at 10:59

38

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.

edited Jun 20 '20 at 10:59

Massimiliano Kraus

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answered Jun 30 '15 at 19:38

Joe Vargas

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score 20 · Answer 3 · answered May 24 '16 at 14:28

20

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);

answered May 24 '16 at 14:28

Ron Rebennack

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This one is worked for me. check this Microsoft article https://support.office.com/en-us/article/How-to-set-up-a-multifunction-device-or-application-to-send-email-using-Office-365-69f58e99-c550-4274-ad18-c805d654b4c4?ui=en-US&rs=en-US&ad=US – wajira000 Mar 09 '17 at 09:22
1

This worked for me, but I had to then go to https://sender.office.com to delist my IP address – Simon Price Jan 30 '18 at 00:18
4

for me sClient.EnableSsl = true; was not defined. – Muhammad Ali Feb 25 '18 at 00:16
8

`You need to set "UseDefaultCredentials" to false first and then set Credentials. If you set "UseDefaultCredentials" after that it resets the NetworkCredential to null.` – Kiquenet May 09 '18 at 09:38
4

How you get the ***MX*** value ? – Kiquenet May 09 '18 at 09:47
1

Which is the difference about `domain-com.mail.protection.outlook.com` and `smtp.office365.com` ? Can I send to xxx@anotherDomain recipients ? – Kiquenet May 09 '18 at 09:58
2

Using the MX record as host enables you to send email only to internal email addresses (ie only to the same domain as the sending address) – Lez Dec 17 '18 at 15:17
1

@Kiquenet You may need to ask your system administrator. More info here: https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365#step-by-step-instructions-for-direct-send – Martijn Oct 08 '20 at 07:07

score 18 · Answer 4 · answered Nov 02 '16 at 12:55

18

I use to have the same problem.

Add the domain solved it..

mySmtpClient.Credentials = New System.Net.NetworkCredential("email@domain.com", "password", "domain.com")

answered Nov 02 '16 at 12:55

Zvi Redler

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This is the correct solution for me. I've had an application running, sending daily emails for over a year, suddenly it stopped working. The change to fix it is this one, even though my network credentials aren't actually my email, this fix worked. – EJA Nov 29 '16 at 15:10
5

It's not adding the domain name, but using the email address as the userName solved my problem. `NetworkCredential(email, password);` – Weihui Guo Nov 01 '18 at 13:19

score 13 · Answer 5 · answered Nov 19 '18 at 17:16

13

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.

answered Nov 19 '18 at 17:16

Daniela

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How is 2 Factor Authentication ? – Kiquenet Oct 08 '20 at 14:45

Mohammad Waqas · Answer 6 · 2021-07-09T06:47:25.280

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

Step 1 worked for me. I had Authenticated SMTP unchecked. When checked and saved, emails started working through my CSharp program. — Chirag, May 29 '22 at 16:37

score 12 · Answer 7 · edited Feb 23 '16 at 08:22

12

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.

edited Feb 23 '16 at 08:22

Chitrank Dixit

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answered Feb 23 '16 at 07:50

Ankush

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score 7 · Answer 8 · answered Nov 01 '16 at 09:57

7

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.

answered Nov 01 '16 at 09:57

Spitz

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I changed only one time. It told me the password expired when I try to login. – Kevin .NET Mar 08 '18 at 20:14

score 5 · Answer 9 · answered Jul 10 '17 at 09:18

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!

score 4 · Answer 10 · answered Sep 24 '20 at 10:53

4

Probably the password of the account that you trying to send e-mail is expired. Just check your password policy expire date.

answered Sep 24 '20 at 10:53

bozok

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score 3 · Answer 11 · answered Dec 15 '17 at 14:42

3

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.

answered Dec 15 '17 at 14:42

horatius83

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Finally a working answer for me. Thanks! I was using a simple string for the To field instead of type MailAddress. The error message is definitely misleading – West May 17 '21 at 08:26

score 3 · Answer 12 · edited Jun 20 '20 at 10:57

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);

score 2 · Answer 13 · answered Jul 13 '17 at 05:10

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.

score 2 · Answer 14 · answered Sep 15 '20 at 22:32

2

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.

answered Sep 15 '20 at 22:32

carlin.scott

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score 2 · Answer 15 · answered Feb 23 '21 at 14:25

2

Try resetting your password for the email used. Had similar issue, and got it fixed only after changing password.

answered Feb 23 '21 at 14:25

Vithu

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score 2 · Answer 16 · answered Jun 03 '21 at 05:20

2

I had similar issue. please read this microsoft support article. specially this section.

answered Jun 03 '21 at 05:20

Vivek kumar

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score 1 · Answer 17 · answered Mar 31 '22 at 14:34

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.

score 1 · Answer 18 · answered Apr 21 '23 at 14:25

1

In my case the problem was solved by dependency update 1.4 -> 1.4.7

<dependency>
  <groupId>javax.mail</groupId>
  <artifactId>mail</artifactId>
</dependency>

answered Apr 21 '23 at 14:25

bausov

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score 1 · Answer 19 · answered Jul 14 '23 at 14:43

In my case, I could compile the program and run it from our server and it ran without issue. When trying to run the program from the VS IDE I would get the same error as the OP. To resolve, I had to add code to detect that I was running the code from the IDE. For my particular situation, when running from the IDE, I needed to turn off SSL. I also wrapped the client in a using statement for easier disposal:

  using (SmtpClient smtp = new SmtpClient())
  {
      if (System.Diagnostics.Debugger.IsAttached)
      {
          // We are running this from the IDE
          //smtp.EnableSsl = true;
          smtp.UseDefaultCredentials = false;
          smtp.Credentials = new System.Net.NetworkCredential(user, pwd);
          smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
       }
       smtp.Send(message);
   }

score -1 · Answer 20 · answered Sep 14 '17 at 11:34

-1

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

answered Sep 14 '17 at 11:34

Justinas Jakavonis

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what language is this? It doesn't appear to be C# SmtpClient() – devlin carnate Mar 28 '18 at 17:54
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It's properties list which can be parsed in any language. – Justinas Jakavonis Mar 28 '18 at 18:24
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How TLS enable in C# ? – Kiquenet May 09 '18 at 09:40
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This is not like C# SmtpClient() – Abdus Salam Azad Jun 19 '19 at 05:18

score -3 · Answer 21 · edited Jun 20 '20 at 11:45

-3

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.

edited Jun 20 '20 at 11:45

Massimiliano Kraus

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answered Feb 14 '19 at 17:46

Freddy Jose Chirinos Moròn

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5.7.57 SMTP - Client was not authenticated to send anonymous mail during MAIL FROM error

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