Server error with Emailing

[Elmo Watson]

I have a script I ran against a database table of emails - - sendning emails
out to all who signed up - -
However, I got the following error, running the script:
The server rejected one or more recipient addresses. The server response
was: 501 5.5.4 Invalid Address

I'm just confused - I would have figured that it would not have any idea
(being server side) whether the email address was bad or good

Since it was ASP.Net - server-side - - does the built in Email namespace
qualify the email address before it's sent?
Or is there some inner-workings that verify the email addresses and send
back data if it's a bad email address?

I searched MSDN - but it only shows up as a BizTalk error.

Does anyone know what's going on here?

 

[Kevin Spencer]

The email was bounced back to the SMTP Server by the SMTP Server at the
other end.

--
HTH,

Kevin Spencer
Microsoft MVP
..Net Developer
Neither a follower nor a lender be.

 

[Elmo Watson]

but I've run this before (using my own email address) and I got bounced
notices in my mail box - it didn't 'crash' the Asp.Net page I was running...

 

[Elmo Watson]

So - does the script check ALL email addresses before it sends, or does it
try to send, sending some, and then stopping when it finds some that bounce?