On a ISPConfig server with PHP running in FCGI Mode, i get following error in error_log when upload images from WordPress admin area.
[Tue Apr 03 13:45:11 2018] [warn] [client 112.133.237.47] mod_fcgid: HTTP request length 139264 (so far) exceeds MaxRequestLen (131072), referer: https://www.url.com/wp-admin/media-new.php
ISPConfig store error log for site in “log” directory in parent folder of document root. In this case, it was
/var/www/clients/client0/web1/log/error.log
To fix the error add
FcgidMaxRequestLen 1073741824
to fcgi.conf
On Ubuntu/Debian, you file location is
vi /etc/apache2/mods-available/fcgid.conf
On CentOS/RHEL
vi /etc/httpd/conf.d/fcgid.conf