systemd vs init.d
Newer Operating Systems like CentOS 7 and Debian 8 both support systemd, and DA is expecting that by default.
A systemd OS will use something like this for restarts:
systemctl restart httpd.service
where the script lives at:
while the traditional init.d uses a more direct script restart with:
CustomBuild itself will auto-detect this for the usual service boot scripts, but the DA binaries do not, as it's an internal default.
If your OS doesn't follow the expected default, such as Debian 8 that uses init.d, that's fine, you'd just need to set
in the directadmin.conf, like this