Workaround for CDO email msg error when sending external emails?

I'm working on an MS Access application that cycles through email addresses and sends an email w/attachments using the CDO message handler.
It works great for email addresses on the local server, but when I try to send to an external email address - I get the error: "-2147220977 - The server rejected one or more recipient addresses. The server response was: 550 5.7.1 Unable to relay for emailaddress@email.com" (where emailaddress is an external email address).

I'm able to send emails from our local network to external folks with MS Outlook fine, so I'm hoping that there is a workaround or another email command I can use with MS Access to accomplish this task?

Here's a code snippet of the method I've been trying to use:
Set objMessage = CreateObject("CDO.Message")
    '==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") = "I put the local server in here"
     'Server port (typically 25)
    objMessage.Configuration.Fields.Item _
    ("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25
     objMessage.Configuration.Fields.Update
    '==End remote SMTP server configuration section==
 
'==Send Email== (contained within a do...loop)
objMessage.Subject = Me.Subject
objMessage.From = Me.From
objMessage.To = rst!Email
objMessage.HTMLBody = Me.Body
objMessage.Send

Thanks for any inputs :)

Start Free Trial