MailMessage.To.Add() throwing exception : "An invalid character was found in the mail header: ','."

Question

I am getting this error when I am using it in sharepoint project, while in console app its working fine

I am using MailMessage class to send email using SMTP . But when I trying to add user to 'To' property I am getting {"An invalid character was found in the mail header: ','."} exception, which I think something fishy is happening here as ',' is allowed to separate multiple users . Adding multiple user

** Multiple e-mail addresses must be separated with a comma character (",").**

MailMessage mailMessage = new MailMessage();

 mailMessage.To.Add("amir_khan@enter.com,walter_white@yahoo.com,");

Possible duplicate? [How to send email to multiple address using System.Net.Mail](http://stackoverflow.com/questions/7498968/how-to-send-email-to-multiple-address-using-system-net-mail) — Izzy, Sep 18 '14 at 08:46
@Izzy Sorry but I tried to search in stackoverflow but can't find any resolution for this particular scenario i.e MailMessage doesn't accepting ',' character while it's written in MSDN. Its regarding the exception — nbi, Sep 18 '14 at 09:00

score 49 · Accepted Answer · edited Nov 20 '19 at 10:47

49

Got the culprit: It's the extra comma(,) at the end of last email address

mailMessage.To.Add("amir_khan@enter.com,walter_white@yahoo.com,");

Just removed that and voila! its working. Don't know why it's working in console application but not in sharepoint :(

mailMessage.To.Add("amir_khan@enter.com,walter_white@yahoo.com");

If this does not work in SharePoint then please add each address separately onto MailMessage object like below;

foreach (var address in StringofEmails.Split(",")) {
MailMessage.To.Add(new MailAddress(address.Trim(), ""));

}

edited Nov 20 '19 at 10:47

ShahidAliK

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answered Sep 19 '14 at 03:43

nbi

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This response is under-rated. This was my problem as well. Thanks. – QuietSeditionist Oct 07 '15 at 15:02
3

Didn't realize it was this easy! Just added .Trim(','); to the end of my string. – Kevin Candlert Nov 04 '16 at 16:10
If you recipients is in a collection you could use `string recipients = String.Join(",", _config.NotificationSettings.MailSettings.Recipients);` – Michael Ushakov Oct 01 '22 at 07:28

Thiru · Answer 2 · 2018-08-16T21:12:53.610

14

I got the error even though I don't have a comma at the end. It turns out that I need to leave a space after the comma

I have to change my code from a string.Join(",", emailList) to string.Join(", ", emailList)

Following didn't work for me.

mailMessage.To.Add("amir_khan@enter.com,walter_white@yahoo.com");

Following worked for me(Observe that there is space after the comma).

mailMessage.To.Add("amir_khan@enter.com, walter_white@yahoo.com");

edited Aug 16 '18 at 21:12

answered Aug 16 '18 at 17:29

Thiru

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This was my issue after I upgraded from .Net 3.5 to .Net 4.7.2. They must have introduced stricter parsing rules. – zemien Feb 14 '19 at 22:57
Placing the space would mean the first is the email (amir_khan@enter.com,) and the second is the name(walter_white@yahoo.com). I dont think it would send it to the second person(walter_white@yahoo.com). Did you confirm it sent to both emails? – Robert Smith May 11 '22 at 17:26
Hey @RobertSmith, Yes it worked when I tried back then using .net framework 4.6+. I didn’t tried it recently. – Thiru May 13 '22 at 06:12

score 2 · Answer 3 · answered Sep 18 '14 at 08:42

2

I can't replicate this. The above code works for me. Maybe try to add them using a seperate 'To' each time.

mailMessage.To.Add(x);
mailMessage.To.Add(y);

answered Sep 18 '14 at 08:42

Stephen Walker

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Thanks. It works, but is there any issue in using specified in question ? – nbi Sep 18 '14 at 09:01
@Nee I couldn't find one sorry, I copied your code directly into my VS and had no problems with it :? Maybe a VS restart might help, or try adding a space after the comma? – Stephen Walker Sep 18 '14 at 09:04
I am getting this error only when I am using it in sharepoint project but not in console application or other – nbi Sep 18 '14 at 09:50
2

There are classes for Smtp in both System.Web and System.Net. In one you must use comma, in the other you must use semi colon. Don't remember which was which. The one in System.Net is the one that is recommended if I remember correctly... – user1429080 Sep 18 '14 at 15:12
1

Semi colon doesn't work with System.Net.Mail.SmtpClient – JayJay Dec 07 '15 at 17:40

score 0 · Answer 4 · answered Dec 22 '15 at 07:59

I had to update a project with nicer looking emails and I published the web project and got this error.

Mine was from some debug code in which

currentUser = myname@mycompany.com

got added

MailAddress mailAddressUser = new MailAddress(currentUser + "@mycompany.com");

Essentially:

myname@mycompany.com@mycompany.com

So instead of an issue with a trailing comma, literally another @

score 0 · Answer 5 · answered Oct 19 '17 at 13:54

0

In my case I forgot to filter out users without email, so I was forming my list of emails like this:

username1@ldomain.com
username2@domain.com
@domain.com  //PROBLEM HERE
username3@linamar.com

answered Oct 19 '17 at 13:54

The One

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MailMessage.To.Add() throwing exception : "An invalid character was found in the mail header: ','."

5 Answers5