I have latest Ispconfig and Nginx running on Debian Jessie. Ispconfig handles hundreds of domains, but now there is a problem with newly created domain, Ispconfig tries to create correct vhost file, but it ends up with vhost.err. It creates standalone vhost file, but there is only information "nginx did not start after modifying this vhost file". Content of vhost file is stored inside vhost.err file and nginx error log file contain the following: 2015/12/21 08:21:11 [emerg] 6510#0: socket() [::]:80 failed (24: Too many open files) 2015/12/21 08:21:13 [alert] 6526#0: socketpair() failed while spawning "worker process" (24: Too many open files) I searched about Nginx error 24: Too many files and tried to increase: • the ulimit hard and soft value in /etc/security/limits.conf • add "session required pam_limits.so" in /etc/pam.d/common-session • increase "worker_rlimit_nofile" in nginx.conf • set "fs.file-max" in /etc/sysctl.conf • set "ULIMIT=-n 100000" in /etc/default/nginx But after server reboot the situation is still the same as before. When I try to manually rename vhost.err to correct vhost file, nginx will refuse to run with the same error 24. Any help would be much appreciated. Thank you!