Please note that our mail server is configured with Authentication.

Below is the code snippet for ASP.

Const cdoSendUsingPickup = 1 'Send message using the local SMTP service pickup directory.
Const cdoSendUsingPort = 2 'Send the message using the network (SMTP over the network).

Const cdoAnonymous = 0 'Do not authenticate
Const cdoBasic = 1 'basic (clear-text) authentication
Const cdoNTLM = 2 'NTLM

Set objMessage = Server.CreateObject("CDO.Message")
objMessage.Subject = "Example CDO Message"
objMessage.Sender = "me@mydomain.com"
objMessage.From = "me@mydomain.com"
objMessage.To = "recipient@test.com"
objMessage.TextBody = "This is some sample message text.." & vbCRLF & "It was sent using SMTP authentication."

'==This section provides the configuration information for the remote SMTP server.

objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2

'Name or IP of Remote SMTP Server
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "mail.your.com"

'Type of authentication, NONE, Basic (Base64 encoded), NTLM
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = cdoBasic

'Your UserID on the SMTP server
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/sendusername") = "youruserid"

'Your password on the SMTP server
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "yourpassword"

'Server port (typically 25)
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25

'Use SSL for the connection (False or True)
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpusessl") = False

'Connection Timeout in seconds (the maximum time CDO will try to establish a connection to the SMTP server)
objMessage.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout") = 60

objMessage.Configuration.Fields.Update
objMessage.Send

Note :
Change the SMTP Server with your mail.yourdomain.com
Username --> Change with your email account in this format (email@domain.com).
Password-> Your email password.