>>>>Is there any particular reason your app can't use the Exchange server directly as its SMTP server? At least for a test, if not in production? In other words
>>>>
>>>>Your Outlook --> Exchange server --> Client && Works
>>>>Your app --> local SMTP server --> Exchange server --> Client && doesn't work
>>>>Your app --> Exchange server --> Client && ?
>>>
>>>I don't know much about Exchange, but is it an SMTP server? We're using SMTP to send these emails in wwipstuff.
>>
>>Actually there's something else you might want to try. That would be to use your ISP's SMTP server, rather than your local SMTP server or Exchange. That should be the most direct and reliable.
>
>Al,
>
>I don't think using Verizon's SMTP server is going to fly at my company.

With your app you should be able to specify any SMTP server you want, even if it's just for test purposes. You could at least see if you still get the error when using Verizon.