All answers we provide expect you’re on a current Zammad version.
And you are, so I have no idea why you are not using the commands that are outlined in the documentation.
You’re using a package installation. Maybe also read the intro of the console section if you don’t know how to handle this.
zammad run rails r 'zammad:email_parser:failed_email:delete path/to/your/email.eml`
which all fail:
╰─➤ zammad run rails r ‘email_parser:failed_email:delete var/spool’
Please specify a valid ruby command or the path of a script to run.
Run ‘bin/rails runner -h’ for help.
(Yes, I changed the placeholder path/to/your/email.eml).
Just for funsies: What would the correct command be to delete/ wipe all unprocessable emails (and/or wipe them from the db) for a packaged installation?