SMTP: Sent Mail – Unable to connect to the remote server —> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it


We were unable to send email using SMTP client. Every time we tried, our event viewer has following entry:


Event Type:    Error

Event Source:    XXXXX

Event Category:None

Event ID:    0

Date:        XXXXXX

Time:        XXXXXX

User:        N/A

Computer:    XXXXXX


Mail Send:error sending email Failure sending mail. at System.Net.Mail.SmtpClient.Send(MailMessage message)

at Mail.Send(String from, String to, String subject, String body, Boolean sendAsHTML) in XXXXXXXXX:line 675 System.Net.WebException: Unable to connect to the remote server —> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it

at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)

at System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP)

at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)

— End of inner exception stack trace —

at System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket& abortSocket6, Int32 timeout)

at System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32 timeout, GeneralAsyncDelegate asyncCallback)

at System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback)

at System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout)

at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)

at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)

at System.Net.Mail.SmtpClient.GetConnection()

at System.Net.Mail.SmtpClient.Send(MailMessage message)

For more information, see Help and Support Center at



McAfee OAS is running on our system and blocks all email. Add exe in the allow list of McAfee.

Virus Scan Console -> Access Protection -> Prevent mass mailing worms from sending mail -> Edit -> Add exe in (Process to exclude list)

You can verify it by checking the logs

Virus Scan Console -> Task -> View Logs



  1. Major props to you! Thanks!

  2. Karthik said

    Excellent piece of info!! Thanks a lot- this worked for me.

  3. Ric said

    You just saved me about half a day’s worth of work. Thank you!!!!

  4. illbreed said

    Thanks!!! this worked great for me!

  5. Anonymous said

    Many thanks. This issue had me stumped for a week!

  6. Piotr said

    U saved my sanity – I could’t even imagine that would be McAfee

  7. Jayanth said

    Perfect! It worked like a charm.

  8. Csaba said

    It was my problem as well. Thanks for your help! Helps a lot

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