It's hard to say what might be the problem. Most likely some proxy or AV issue...

I'd still recommend looking at a more recent version and using the .NET module as it handles many more mail server scenarios than the old DLL based version does. You might get additional error info that might point at the problem.

What is the error message on those failures anyway?

+++ Rick ---

>Rick,
>
>We are sending first to a SMTP server from VFP9 using a pretty old version of wwipstuff and the it goes out the door via our Exchange server. So, as a protocol SMTP is correct, I believe.
>
>Again, the failures are only to 2 customers out of 100. All 98 other emails to our customers successfully go through.
>
>>How are you sending the emails exactly? All going through the same mail server or sending to different mail servers?
>>
>>wwIPStuff only worked with a few protocols. wwSmtp (which is the later version with the same interface) supports a much wider variety of protocols including support for SSL connections for servers like gmail, outlook.com etc.
>>
>>The error looks like the server send some command that the client doesn't understand and subsequently hangs. If you use wwSmtp especially in .NET mode this is very likely to go away.
>>
>>http://west-wind.com/webconnection/docs/_s9001zxj2.htm
>>
>>+++ Rick ---