For each site, Apache writes access and error information to log files.
Each site has two log files - access_log and error_log, which
store information on access to that site and errors respectively. Apache
log files for each site are located in the /statistics/logs
subdirectory of the virtual host directory
/var/www/vhosts/< domain_name >, where domain_name is
the name of a corresponding domain.
To save disk space, Plesk rotates Apache logs. Learn how to change log
rotation parameters in the Log rotation section.