A customer is missing here custom IMAP folders all of a sudden. In Thunderbird the folders are cursive visible but empty, in Roundcube the folders are completely missing. In DirectAdmin I can see that the size of the mail account is still original, so the data is there, but not visible anymore.
dovecot 2.3.18 (9dd8408c18)
Exim 4.95
Normally then they have themselves deleted or
moved ( without knowing) some in the client, if not themselves, and other imaps on server are ok.
Then a software or ?? "hacker" did
But check first on other custom imap folders on that box , are they ok?
( Updates on box? ) Userrights changed?
Settings for purge/ deletion after x time...? ( or even the view/ folder setting in client)
Language i don't know but had for long time problem between English and Dutch, switching.
Check test yourself if you make custom IMAP folders or you can see them in Roundcube.
Could be (i had onetime) she had become a new ( or kind of reinstalled,) computer?
ERROR or other LOGS for that user on your server?
Whith SSH you could go to that users folder and see if the mails are there, don't know which folder / place but this should be possible,.
