Getting an error when sending email using CDOSYS

The error  The "SendUsing" configuration value is invalid is received because you need to specify which server to send the mail from. Please try:

'Name or IP of remote SMTP server
myMail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserver")="127.0.0.1"
'Server port
myMail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserverport")=25
myMail.Configuration.Fields.Update

In very specific cases (on older servers), you may be able to use mail.SERVER.arvixe.com for the smtpserver value instead of 127.0.0.1