Service not available, closing transmission channel RRS feed

  • Question

  • Hi Folks,

    I am facing an issue with SMTP, getting  Service not available, closing transmission channel. The server response was: 4.4.1 Connection timed out" error.

    I am trying to send email from server object model to around 1000 recipients and below is the my code.

     string SMTPServer = SPAdministrationWebApplication.Local.OutboundMailServiceInstance.Server.Address;
                                SmtpClient smtpClient = new SmtpClient(SMTPServer, 25);
                                smtpClient.Timeout = 1200000;
                                smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;                            


    Thanks. khadar pasha

    Thursday, September 18, 2014 2:17 PM


All replies

  • Try below:


    Which mail server are you using. Inrease its timeout Incase using exchange follow below:


    Try to modify the following settings of the receive connector is capable of receiving mails from your programs:

    Open EMS, type:

    Set-receiveconnector -identify "your receiveConnector" -connectiontimeout:00:30:00 

    If this helped you resolve your issue, please mark it Answered

    Thursday, September 18, 2014 2:23 PM
  • Try running the Network Monitor tool and see if there are blocks in network call.


    If not, you can try increasing the timeout limit suggested by Inderjeet

    Please mark the replies as answers if they help or unmark if not.

    Friday, September 19, 2014 5:06 AM
  • hi

    there are several possible reasons:

    1. remote server which is specified in SPAdministrationWebApplication.Local.OutboundMailServiceInstance.Server.Address doesn't respond

    2. port 25 is blocked by firewall

    Try to connect to your smtp via telnet (How to check an SMTP connection with a manual telnet session) at first from your Sharepoint server and then from some other server. If connection from other server will work, the problem is in firewall settings. Check the following post about opening port 25 in Windows firewall: How to Open Port 25.

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    • Marked as answer by JasonGuo Sunday, September 28, 2014 8:07 AM
    Friday, September 19, 2014 5:37 AM