Delivery failed: Invalid Addresses

[Lexie]

Hi Everyone,

I am having issues sending mails from one of my accounts on Zimbra Desktop 2. I have Zimbra Desktop installed on my Ubuntu 10.10. I do not use Collaboration Suite.

I am able to receive and send mails from 4 other accounts set up on my Zimbra desktop, but cannot send mails from my primary (default) account. I get the error: " Delivery failed: Invalid Addresses", each time I try to send mails from this particular account.

I will be grateful to receive help with this problem.