DescriptionThis article provides a solution on how to resolve "421 4.7.0 closing connection" errors which prevent SMTP connections to be established to the FortiMail unit.ScopeAll FortiMailSolutionEmail users may encounter the following error message when trying to make an SMTP connection attempt to the FortiMail unit:
"421 4.7.0 smtp.example.com closing connection"
This problem may occur due to the internal database being corrupted for greylisting, dictionaries, white list and black list.
To confirm whether this is the case, try to access these options from the FortiMail GUI; the following error message should be displayed:
"ipc_read failed. rc = 0 length 4"
Warning: To prevent any loss of data it is recommended to schedule a maintenance window and to take a backup of all your mail data before continuing.
To recover a corrupted database the entire mail disk will have to be formatted by executing the command below from a CLI window:
- exec formatmaildisk
Following a successful format of the disk and a reload of the FortiMail unit, restore the mail data from its backup location.
