SymptomsSystem users' home directories created by the Parallels Plesk Panel are not placed in subdir of HTTPD_VHOSTS_D. For example:
# grep HTTPD_VHOSTS_D /etc/psa/psa.conf
# grep sysuser /etc/passwd
After an upgrade to Parallels Plesk Panel 10.x, there will be an internal error when clicking to "Websites & Domains" in the Control Panel for such domains:
Internal error: /var/www/vhosts/domain.tld/httpdocs is out of webspace
ResolutionModify the system user's home directory to a new location in /etc/passwd file and in a psa database in the sys_users table before upgrading to Parallels Plesk Panel 10.x version.
Also this solution is applicable to destination server after migration.
If vhost location has been changed from /var/www/vhosts/ to /home/httpd/vhosts/ for each system users you should change home directory in the /etc/passwd and home in table sys_users from /var/www/vhosts/domain.tld to /home/httpd/vhosts/domain.tld