I've just started using Zimbra after years using another M$ product.

I'm wondering if theres any special to thing of when doing a forward of an account?

I created an account and added the address which the account should be forwarded to in the tab "Forwarding" on the Account details page.

But it seems like that some of the mails are being deferred. I get this message:
451 Could not complete sender verify callout

After some googleing I found this http://support.aguk.net/article.aspx?id=10153

As what I can understand, this depends on that Zimbra takes the email and send it to the forwarded address. But when that server performs a back check with the Zimbra server it can find the original senders address.

Anyone else with this problems?

Any ideas on how to solve it?