Not sure if this is the right forum, but ...

I have a client that is getting the error every time he tries to send out an email as shown in image the attached.

Claims it started happening in the midst of sending out other emails and now can't send any.

In the same office on the same network another person using the same code and older versions wwDotNetBridge and wwIPStuff DLLs (2010) and reading from the same data to populate the variables has no problem sending out email.

They claim they're both running Windows 10.

Any ideas?

There's no image attached so no further info here...

Invalid argument seems to be some sort of invalid value for recipient or sender most likely, or perhaps the mail server. More info is needed to see what was actually passed to the object.

+++ Rick ---

Sorry about not uploading the image ... here it is ... The user that is successful is using the same Sender, Recipient, and Mail Server ... I'll try to get more information. Thanks for the quick response ...

You probably are going to have to look at the object when the error occurs - put an exception handler around the Send and capture the state of the object. Almost certain it's invalid address (email) or server name.

+++ Rick ---