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

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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);
     }
  } 
 }

Hydrops answered 20/5, 2015 at 7:20 Comment(4)

why not increase the Timeout? – Tenuto 20/5, 2015 at 7:48

Did you anonymize this, or are you actually trying to send over office.com with that login? – Synopsize 20/5, 2015 at 7:48

@reshma, What changes did you make? Facing the same issue. – Guanajuato 23/10, 2017 at 4:26

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 – Galley 19/6, 2019 at 15:49

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39

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.

Hagride answered 30/6, 2015 at 19:38 Comment(0)

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50

@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.

Plumbic answered 8/7, 2015 at 10:19 Comment(4)

That's it! I didn't know "UseDefaultCredentials" clears the Credentials. Thanks! – Packton 21/7, 2016 at 20:3

In my case, it doesn't matter which one goes first. As long as the "UseDefaultCredentials" is false. It works. I wonder why. – Disingenuous 31/10, 2018 at 11:57

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): mysignins.microsoft.com/security-info – Telegraphese 20/7, 2023 at 2:34

The important word is THEN. FIRST do "UseDefaultCredentials=false" and then set your own credentials. Tricky if you don`t know that! – Backwoods 30/1 at 15:36

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39

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.

Hagride answered 30/6, 2015 at 19:38 Comment(0)

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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("[email protected]");
        message.Subject = "Test";
        message.CC.Add(new MailAddress("[email protected]"));

        sClient.Send(message);

Bimonthly answered 24/5, 2016 at 14:28 Comment(8)

This one is worked for me. check this Microsoft article support.office.com/en-us/article/… – Vaisya 9/3, 2017 at 9:22

This worked for me, but I had to then go to sender.office.com to delist my IP address – Individual 30/1, 2018 at 0:18

for me sClient.EnableSsl = true; was not defined. – Footlambert 25/2, 2018 at 0:16

You need to set "UseDefaultCredentials" to false first and then set Credentials. If you set "UseDefaultCredentials" after that it resets the NetworkCredential to null.

– Placet 9/5, 2018 at 9:38

How you get the MX value ? – Placet 9/5, 2018 at 9:47

Which is the difference about domain-com.mail.protection.outlook.com and smtp.office365.com ? Can I send to xxx@anotherDomain recipients ? – Placet 9/5, 2018 at 9:58

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) – Synder 17/12, 2018 at 15:17

@Placet You may need to ask your system administrator. More info here: learn.microsoft.com/en-us/exchange/mail-flow-best-practices/… – Transaction 8/10, 2020 at 7:7

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I use to have the same problem.

Add the domain solved it..

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

Oyler answered 2/11, 2016 at 12:55 Comment(2)

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. – Psychopathy 29/11, 2016 at 15:10

It's not adding the domain name, but using the email address as the userName solved my problem. NetworkCredential(email, password); – Disingenuous 1/11, 2018 at 13:19

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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

Dillie answered 9/7, 2021 at 6:40 Comment(1)

Step 1 worked for me. I had Authenticated SMTP unchecked. When checked and saved, emails started working through my CSharp program. – Lathe 29/5, 2022 at 16:37

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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.

Kroll answered 23/2, 2016 at 7:50 Comment(0)

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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.

Amperage answered 19/11, 2018 at 17:16 Comment(1)

How is 2 Factor Authentication ? – Placet 8/10, 2020 at 14:45

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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.

Seduction answered 1/11, 2016 at 9:57 Comment(1)

I changed only one time. It told me the password expired when I try to login. – Sacha 8/3, 2018 at 20:14

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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!

Subsequence answered 10/7, 2017 at 9:18 Comment(0)

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

Shererd answered 24/9, 2020 at 10:53 Comment(0)

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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.

Zaragoza answered 13/7, 2017 at 5:10 Comment(1)

I did not want to change my password so I used a newer account that I had set up recently and it worked! I think it has something to do with stale passwords! – Shalne 15/6 at 22:45

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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.

Voltmeter answered 15/12, 2017 at 14:42 Comment(1)

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 – Archine 17/5, 2021 at 8:26

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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);

Caneghem answered 17/11, 2019 at 0:28 Comment(0)

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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.

Grory answered 15/9, 2020 at 22:32 Comment(0)

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

Bittencourt answered 23/2, 2021 at 14:25 Comment(0)

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

Mayamayakovski answered 3/6, 2021 at 5:20 Comment(0)

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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.

Vesuvian answered 31/3, 2022 at 14:34 Comment(0)

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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>

Tibetan answered 21/4, 2023 at 14:25 Comment(0)

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1

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);
   }

Charlacharlady answered 14/7, 2023 at 14:43 Comment(0)

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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
[email protected]
mail.smtp.password=xxx
[email protected]

Hitormiss answered 14/9, 2017 at 11:34 Comment(4)

what language is this? It doesn't appear to be C# SmtpClient() – Corwun 28/3, 2018 at 17:54

It's properties list which can be parsed in any language. – Hitormiss 28/3, 2018 at 18:24

How TLS enable in C# ? – Placet 9/5, 2018 at 9:40

This is not like C# SmtpClient() – Deprive 19/6, 2019 at 5:18

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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.

Pasteurizer answered 14/2, 2019 at 17:46 Comment(0)

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