[fmail_fan]

I'm still trying to get a Mac client app that will connect up with FastMail and consistently retrieve and display all of my personal folders. I've been working with the Mac Mail app, AirMail 3 and PostBox. I'm also experiencing problems with my Android app (BlueMail) that had been working fine up until a few days ago. The 'standard' folders (Inbox, Sent Items, Trash) are always displayed correctly. Some personal folders get displayed in the clients and then disappear when viewed later after an app restart. At the moment the Mail app is not showing messages in any personal folder.

I've tried restarting the apps, resynchronizing the FastMail account, removing and recreating the account, clearing caches, trying new app passwords, new server names as well as the messagingengine, restarting the Mac and restarting it in safe mode. I have not specified an INBOX path prefix. The (new) FastMail web interface and FastMail Android app work fine.

Does anyone know if FastMail support has access to logs that might show some type of error condition for my account access?

UPDATE
FWIW, scanning local Mail.app logs I find the following error line scattered throughout the log file 2016-08-05_IMAPSyncActivity.log"
Aug 5 11:05:44 Mail[966] <Debug>: [Fastmail] Account sync failed with error: Error Domain=MCMailErrorDomain Code=1030 "The IMAP command “STATUS” failed with server error: Mailbox does not exist." UserInfo={NSLocalizedDescription=The IMAP command “STATUS” failed with server error: Mailbox does not exist.}