Migrating from Mozilla Thurderbird/Lightning and trying to get an archive folder imported into Zimbra Desktop.

From other posts I have learned that I needed to get the files into a readable format for Zimbra.

Have been able to take the multiple steps to export and then archive (.tar) and then convert finally into .gz but get the "Not allowed to import to root folder for this type".

Was trying to import into local folders. Also tried to import into an imap account folder but no luck in either.

Would love some advice...can't lose all of my archive emails and need to continue to be able to add to those file folders.