Our old non-InterWorx box apparently supported the IMAP NAMESPACE extension, but our newer InterWorx box does not (or it does not work). See this URL for mostly related info: http://www.courier-mta.org/FAQ.html#namespace. The main symptom of the namespace value being defined incorrectly (or not at all) is the email client fails to copy anything to the Inbox subfolders, including “Sent” and “Drafts”.
We usually tell clients that want to use IMAP to set their namespace values, ignoring the fact the server should be supplying those values automatically. This worked fine, until yesterday when a client brought Apple Mail to the table, an email client that does not appear to provide that option for the end user. Probably a by-product of Apple trying to simpify the user experience.
Apple Mail does provide an IMAP prefix option, but while that is similiar, it is not the correct configuration option to change. I have attached my Thunderbird Advanced Account settings, which work perfectly, except for the fact I had to manually enter them.
Does anyone know how to fix this? I have had very little luck with it, and now it is directly affecting a new customer…
Note: I think this may be an InterWorx bug, because I have not altered my out-of-box configuration for Courier IMAP.