Hello,
Some of our clients get mails twice from different e-mail addresses. Why this is happen? To avoid this what we do from our side? They complained a lot. But when we send mail to them , they get only one. I examine the message source, ie same for dupluicated mails. Due to this problem their traffic is increased, what we do? I expect an immediate answer.
Thanks in advance
Chirayil

You expect? LOL Now that's funny. You do realize this is a USER supported forum, right? The only EV1 people you'll see here are the Sales folks, not Support. File a trouble ticket if you want an official answer.

As to your question, we'll need a LOT more information. The relevant snippet from your maillog and the actual headers of these duplicate emails would be quite helpful. If I had to guess, you probably have the domains set up with a Catchall that forwards things over to a single address. So when someone sends them an email with a CC or BCC to another email address on the domain, both end up getting forwarded to the lone catchall address.