Roundcube Mailbox doesn't exist: Trash
Have a look in /var/lib/roundcube/config/defaults.inc.php (in Ubuntu 16.04.1) if the following lines exist and are correct ——————————————————————————————————— // store draft message is this mailbox // leave blank if draft messages should not be stored // NOTE: Use folder names with namespace prefix (INBOX. on Courier-IMAP) $config[