After update Debian and PHP I have the following problem: If I change the domain name in ISPconfig (eg from subdom.domain.com to subdom1.domain.com) apache will display "Apache2 Debian Default Page". Renaming back (eg back to subdom.domain.com) does not help. Still showing "Apache2 Debian Default Page". Changes are visible in the "/ etc / apache2 / sites-available" and "/ etc / apache2 / sites-enabled" directories. The virtual hosts I did not rename, works fine, even after the Apache restart. Thank you for help.