in cPanel some email accounts suddenly disappeared. Folders for email accounts did not disappear, they do exist in /home/username/mail and all the information was there
you notice that one or more email accounts have gone missing here is how to fix this
restore this file from backups
/home/user/etc/domain/shadow if you do not have backups, open /home/user/etc/domain/shadow file with an editor on your own option. copy one of the entries to recreate the entries for your missing email accounts.
Emails are still disappeared in cPanel
mv /home/user/.cpanel/email_accounts.json /home/user/.cpanel/email_accounts.json.backup reset the passwords of missing emails