Sorry. I search solution in internet and found same problem in red hat page and c&p from there (https://access.redhat.com/solutions/4992301).
Our mail server has been reboot while updating. Boot files has been corrupted and I reinstall it.
When system is loading it now is
core verion is 3.10.0-1127.8.2.el7.x86_64
OS: NethServer release 7.8.2003 (final)
I am update from web interface (cockpit).
Backups not present (we have 2TB of mail files).
Now I have 24 hour to restore access to mail.
Can I dismiss from using LDAP?
Can I setup LDAP server on another machine and add same users to it and configure failed server to use another LDAP?
Can I reinstall system without lost mail?