centos7 apache cannot write to a file it owns
It's likely an SELinux permissions issue.
/var/log/audit/audit.log should be able to confirm.
SELinux context is probably
system_u:object_r:httpd_sys_content_t:s0, but should be
system_u:object_r:httpd_sys_rw_content_t:s0. This can be altered with
I'm also not sanguine about having a config file within the
DocumentRoot of your webserver. I could be mistaken as you haven't provided enough detail, but that would be the case if you haven't altered the defaults.