Not sure if it's a bug, or me doing something wrong. However, I've tested this on two Debian Edge servers with ISPconfig 2.2.13 on it. When I enter an email address in the "Forward" option in the "ISPconfig's User & Email > Advanced Settings" option, the email does not get forwarded. The email address used to forward to is on the same server, but not the same domain. Again. I'm not sure if this is a bug, or me doing something wrong.
It's not a bug Hi Edge, To verify if it is a bug or not, I did the test with "keep copy" enabled and also without "keep copy". I must say that the forward function is working as it should. For this reason, my conclusion is that it is not a bug. Please make the settings again and press "Save" when you get back on the basic tab of the website. Maybe that helps...
When (for me) the forwarded email address used is not on the server it's working fine, but when I use an email address that is on the same server, it's for some reason not working here.