After you log into your cPanel account, you notice that one or more email accounts are missing. You access the main email accounts interface, the list of email accounts is either incomplete or empty.
If the list of email accounts is empty or if users are missing, and you are sure they exist, examine the files /home/domain/etc/domain.com/shadow and /home/domain/etc/domain.com/passwd. If you have backups of these files, you will want to restore them.
If there are no backups, edit the shadow and passwd files and copy one of the existing entries to recreate the entries for the missing email accounts. You can also consider modifying each newly created password hash by adding a few characters to avoid duplicating the password for each account.
You need to add a new username for your address, as you can see in the second screenshot:
You need to perform the same steps in the shadow file:
Note that you need to change two or three letters in the password field, so that the password cannot be duplicated.
Once done, if your email accounts still do not appear in the interface, rename the email account JSON file located in /home/domain/.cpanel/email_accounts.json
Finally, reset the password for each of the recreated users. To do this from cPanel, please consult the following article: How to change the password of an email account ?