SMTP Problem

Hi,

I've wrote a program which can send e-mail reports.
I use the Indy SMTP component for this procedure.

What I found out is: Some providers do not accept
emails that were created with Indy, some (the most) do.
I think there were to much spamers they've used Indy
maybe and that's why some smtp servers do not
accept any mail (header) that looks likeit came from
a programm with Indy component?

But how can I send an email to such providers?

Any help would be kind.

thanks.