Postfix server config problem not receiving emails

Hi,

I’ve really strange problem. My server stopped receiving emails, the sending was fine. After hours of checking logs and config files, I realized that main.cf was messed/erased? It looked like basic postfix config. I needed to restore missing functions like

alias_maps = hash:/etc/aliases or bbc maps
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME

After adding them it started to work.

What could happen here?