We have been using the email: [email protected] in our email forms. This is an alias for the email: [email protected].

This alias has worked fine up until I moved the ASP pages to another server and left the HTML pages on the old server.

Now I have to use [email protected] in order to receive mails through this form again.

Can someone explain why is this?

There are too many variables to properly answer this question...

The basics is that, with the advent of the proliferation of spam email, that many ISP disallow sending email unless the FROM address is a real email address.

Or they disallow sending email, except when the sending address is within their own domain (e.g. [email protected]).

If you would have bothered to mention what object model you are using it would have been helpful in answering your question fully.

I know in the case of CDONTS that you can even leave the FROM field blank and it will send.

I've run into this problem many times.

I am using CDONTS.
You probably right about the security issue because the reason of me moving my ASP pages was that they were upgrading their servers (and services), to provide higher security and shut down my asp service.
As of sending the form with FORM fields left blank, I just solve the issue with validating fields as much as possible.