Develop Reference

Does anyone know ow to fix this issue sending SMTP messages to Gmail accounts?

I am having an issue with sending emails specifically to Gmail-related accounts, and I'll be darned if I know what the issue is. This is a C# ASP.NET project, by the way.
First, the following code works, as long as I am sending to any email account OTHER than a Gmail account:
var mail = new MailMessage {
Subject = "test email",
Body = "this is only a test",
Priority = MailPriority.High,
IsBodyHtml = true,
From = new MailAddress ( "<outbound email here>" )
};
var msgID = Guid.NewGuid().ToString();
var sentBy="<outbound mail domain>";
mail.Headers.Add ( "message-id", $"<{msgID}>");
mail.Headers.Add ( "msg-id", $"<{msgID}#{sentBy}>");
mail.To.Add ( new MailAddress ( "<recipient email>" ) );
var smtpClient = new SmtpClient("<email server address>") {
Port = 587,
Credentials = new NetworkCredential("<sender's email address>", "<password>"),
};
smtpClient.Send ( mail );
I have removed email addresses and network credentials, obviously.
The code works, because as long as I send email to a NON-Gmail account, it comes through just fine. But anything going to a Gmail-related account never arrives.
I added the two lines in the code above to add a message ID to the header based on what I read in several older posts here about some mail servers, like Gmail, rejecting email messages that didn't include them, but it has not fixed the issue, and I'm out of ideas. My ISP says the SPF record for the mail server is fine, so according to them that's not the issue.
Has anyone else encountered this recently, and if so, how did you fix it?
To clarify, the comments/answers I have received so far are appreciated, but as I stated in the OP, this is a problem with sending emails TO Gmail accounts. I am using my ISP's mail server to send them, and I am adding a message ID to the header to address what the log says, that the message is missing a message ID and won't be accepted. I can send emails to other non Gmail accounts just fine, and when I inspect the headers they show a message id. So I don't know why this continues to be an issue.

So the answer to this is that the issue was related to changes Google made to policies for sending emails to Gmail accounts, which might require adjustments to the SPF record on the sending SMTP server. That was the case in this situation - the hosting company was slow to respond (took them more than a week) and had to elevate the issue to their Tier 3 techs, but once the SPF record was fixed to account for Google's changes, all was resolved.

Button in Email click to create new email with content

Introdution
I am currently working a system develop with C#.
The system is about request approval.
When a request made, system will send email to user ask for response.
User's response will as simple as approve, reject or request update.
Question/Problem
Is it possible to have a button (approve or reject) in email content which allow user to response to system with only one click but without open browser?
Or, Is it possible to create button in email content which enable user to click to create new email with pre-set subject and recipient like following:
subject: request id - 123 - action - approve
to: response#system.com
as response email for user to send.
Then system can then recognize the email received and perform required back-end process.
Research Done
Research 1
What I currently found was outlook appointment email.
it done like second solution create new email with content for user send a response.
But, it only have options accept, decline and tentative.
And, I am not sure is blackberry support it like outlook.
The following is the blog found to create appointment email:
http://chuckdotnet.blogspot.my/2007/10/send-outlook-meeting-requests-with.html
Research 2
The following website teach you how to create hyperlink in email content which can create new email with pre-populate subject, body, and recipient
https://community.articulate.com/discussions/building-better-courses/hyperlink-to-create-an-already-written-email
However, No test had perform in blackberry yet.
Appreciate for any suggestion from you guys and I willing to try.

Is it possible to sent an email with button which can click to create
email with some pre-set content?
Yes, this is possible, see the System.Net.Mail code in the .NET framework.
https://msdn.microsoft.com/en-us/library/system.net.mail(v=vs.110).aspx
You can also see this StackOverflow question about how this is used.
Send e-mail via SMTP using C#
MailMessage mail = new MailMessage("you#yourcompany.com", "user#hotmail.com");
SmtpClient client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.google.com";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);
Finally, your code should fire a serverside post on button click to have the server take care of sending the email. If data needs to be posted to the server, you may want to consider putting this data in a form input, which will post to your controller. You can then take that data and build the email with the example I provided in the links.

Restricting replyTo Field in SMTP (C#)

Is it possible to restrict the user to reply to a mail sent via SMTP server?
I have tried using obsolete before the method name but still reply mail could not be blocked
void sendmail()
{
string to = "abc#xyz.com";
string from = "def#abc.com";
MailMessage message = new MailMessage(from, to);
message.Subject = "Using the new SMTP client.";
message.Body = #"Test"
SmtpClient client = new SmtpClient(server);
client.UseDefaultCredentials = true;
}
above is the sample code.

As others have said in the comments, it is impractical/impossible (depending on level of access to their computers) to prevent a user replying to an email. However, you can prevent an exchange email account from receiving emails by applying delivery restrictions - telling the account to only receive emails from itself:
On the server running Exchange start "Active Directory Users and Computers"
Find the account.
Double click the account to open its properties (or right click and select "Properties")
On the "Exchange General" tab, click [Delivery Restrictions...].
Under "Message restrictions" check "From authenticated users only". Then select the radio button "Only from" and add the user account. It is important that you add a user account here otherwise Exchange will accept email from any authenticated user.
Click [OK] to close the "Delivery Restrictions" dialog and [OK] again to close the account properties dialog.
Using this method, to any other user it will look like the account does not exist and they will receive delivery failed messages.
This an other methods are detailed here: http://www.cryer.co.uk/brian/msexchange/exch_howto_disable_delivery.htm

Email Support section with the users address as "From address"

I need to implement a “email support” section in our application. So email “To” address will be admin#mydomain.com” and from address will be the email address of the end user.(The end users email address may be on the same domain or another domain like user#mydomain.com or user#gmail.com).
In the application I am authenticated the email using admins account details (username and password)
System.Net.NetworkCredential("admin#mydomain.com", adminpassword);
Also I am using host address as “mail.mydomain.com”
Issue is I am getting the following error:
“Mailbox unavailable. The server response was: From address must
match authenticated address” error message.
Is it possible to send an email with the correct sender email address(users from address)
My code sample is
message.To.Add(“admin#mydomain.com”);
message.From = new MailAddress(“test#gmail.com”);
message.IsBodyHtml = true;
message.BodyEncoding = Encoding.UTF8;
var smtp = new SmtpClient("mail.mydomain.com");
smtp.Credentials = new System.Net.NetworkCredential(admin#mydomain.com, adminpassword);
smtp.EnableSsl = false;
object usrtkn = message;
smtp.Send(message);

In general the From address shouldn't be the user themselves, it should be an internal system address. This is mainly because the user isn't actually sending the email, the application is. In the email itself you can specify which user sent it (and what their email address is). You can perhaps even specify the user's email address in the ReplyTo field of the message.
But the message you're getting from the SMTP server pretty much says it all. If the message is "from" that user then the SMTP server refuses it because it's sensitive to authentication and origination of emails. To the SMTP server (to any SMTP server I would imagine) it looks like you're trying to spoof messages.

You cannot do what you are doing, because the SMTP server is not allowing you to "impersonate" the user's email address for sending to the system. And thank goodness this is the case or else people would be spamming/spoofing the heck out of everyone under someone else's name.
Why are you trying to have it appear that the user is sending an email to the application? Why not just have a support section of your application where users can "submit" requests for support to the system and then if you want to send emails out to the users, then your scenario will work, but just in reverse (where the system is the From address and the user is the To address).

I use Golang, I skill put the "From" int othe message
msg := []byte(
"From: root#myserver.com.br\r\n" +
"To: destiny#myserver.com\r\n" +
"cc: destiny2#myservercom\r\n" +
"Subject: Why are you not using Mailtrap yet?\r\n"+
"\r\n"+
"Here’s the space for our great sales pitch\r\n")
auth := smtp.PlainAuth("", root, password, host)
err := smtp.SendMail(address, auth, root, destinationEmail, msg)

Is it possible to send an email programmatically without using any actual email account

I'm thinking of implementing "Report a bug/Suggestions" option to my game, however I am not quite sure how I could get that working. I do not have my own server or anything, so I can't just send the text that user has written to there.
The only way I came up with is that the client would write a message and I would send it to an email account where I could read them. However, I do not want that users would need to send the reports through their personal accounts. I am not quite sure how I could implement this and googling didn't bring up any good suggestions.
I haven't done a lot of network stuff, so I'd really appreciate it if you could explain ( possibly even in code ) the process step-by-step.
I am using C# and the game is being programmed for Windows Phone 7.

Yes, it is absolutely possible to do that. From a relatively low-level perspective, you need to:
Resolve the MX (mail-exchanger) server for the e-mail account you want to send to.
Open a socket to the MX server.
Send the appropriate SMTP commands to cause the e-mail message to be delivered to your recipient account. You essentially have the freedom to set the "from" address to be any arbitrary thing you want.
SMTP is a very simple/human-friendly protocol, so it's not a massive effort to do all of that by hand. At the same time, there are prebuilt libraries that will handle all of that for you (except possibly the resolution of the recipient's MX server).
Note that emails sent this way are more likely to be filtered out as spam (generally because the sender's IP/hostname is not going to match whatever domain you put on the outgoing e-mail address you decide to use).
Also note that since you can set the "from" address to anything, you have the option of asking the user if they want to provide their actual contact address, and if they do you can make that the "from" address so that you can actually get back in touch with them if necessary.

You don't need to use email at all. Consider using an error reporting service like sentry or airbrake.
These services have clients that you embed in your program; which automatically log your errors, including any debugging information/stacktrace; and notify you by email when your application reports a problem.
Usually you integrate the app's API into your own error handling mechanism. At the point of an error, the client will capture your debugging information, you can popup a modal asking user for information like "what were you doing when this error happened?", save that as part of your error response that is sent back to the service.
Since the app works over HTTP, you don't need any special ports to be open. It is easier and more helpful than having users send you emails with "it doesn't work!!", and you don't have to deal with email sending headaches.

I recently wrote an article on this: Sending email with C#
You basically have two choices, either you send it using an SMTP-client, this means that you have to have a SMTP-server and be able to connect to port 25 (if you're not using an external SMTP, then you have to manage that by yourself). Or you can use an external email provider, such as:
AlphaMail
SendGrid
Mandrill
If you're using AlphaMail you can send emails in the following way:
IEmailService emailService = new AlphaMailEmailService()
.SetServiceUrl("http://api.amail.io/v1/")
.SetApiToken("YOUR-ACCOUNT-API-TOKEN-HERE");
var person = new Person()
{
Id = 1234,
UserName = "jdoe78",
FirstName = "John",
LastName = "Doe",
DateOfBirth = 1978
};
var response = emailService.Queue(new EmailMessagePayload()
.SetProjectId(12345) // ID of AlphaMail project (determines options, template, etc)
.SetSender(new EmailContact("support#company.com", "from#example.com"))
.SetReceiver(new EmailContact("Joe E. Receiver", "to#example.org"))
.SetBodyObject(person) // Any serializable object
);
Another thing that differs from just building HTML and sending it with an SMTP-client is that with AlphaMail you have the ability to edit your emails outside your code directly in a GUI. You can also easily create highly dynamic templates using AlphaMail's templating language Comlang.
<html>
<body>
<b>Name:</b> <# payload.FirstName " " payload.LastName #><br>
<b>Date of Birth:</b> <# payload.DateOfBirth #><br>
<# if (payload.Id != null) { #>
Sign Up Free!
<# } else { #>
Sign In
<# } #>
</body>
</html>

So this is my thought, why don't you have the email sent to you...as you?
using System.Net;
using System.Net.Mail;
var fromAddress = new MailAddress("from#gmail.com", "From Name"); //Both the email addresses would be yours
var toAddress = new MailAddress("to#example.com", "To Name"); //Both the email addresses would be yours
const string fromPassword = "fromPassword";
const string subject = "There name or whatever";
const string body = "Errors ect....";
var smtp = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};
using (var message = new MailMessage(fromAddress, toAddress)
{
Subject = subject,
Body = body
})
{
smtp.Send(message);
}
code from here
All they would see would be the submit button so they wouldn't have all your personal username/password, also you should prolly set up a dummy account to have them sent to even if it just then forwards them to your real email account.

Another way to achieve this would be to host a WCF Service which takes in your Message and stores in db or /sends email. One downside of this is you'll need a web server to do this.

Try following code this might help you :
Dim objCDOMail
Set objCDOMail = Server.CreateObject("CDONTS.NewMail")
objCDOMail.From = "sender#domain.com"
objCDOMail.To = "receiver#domain.com"
objCDOMail.Subject = "Test Mail Script"
objCDOMail.BodyFormat = 0
objCDOMail.MailFormat = 0
objCDOMail.Body = "Testing Mail from Test Script"
objCDOMail.Importance = 1
objCDOMail.Send
Set objCDOMail = Nothing