Unhelpful error message when creating mailbox

When creating a mailbox on a domain that has a default forwarding address setup it is possible to get a confusing error message:

Failed to save mailbox : '' is not a valid email address

In short, if they delete the Email Forwarding Destinations text field, without setting the dropdown to None, they get this error, which led to the customer thinking there was some kind of bug (after all, they had an address in the Name field at the top).

This error ought to be a bit more specific about where the problem is. Perhaps just adding the word "forwarding" in there before "email address" will do the trick and provide enough of a hint of the trouble.

Closed (fixed)