I'm using nginx on the frontend as "proxy cache" and apache on the backend, i've set my PHP settings to the following:

error_log = /var/www/site1/php_error.log
error_reporting = 22527
file_uploads = On
log_errors = On
max_execution_time = 0
max_file_uploads = 20
max_input_time = -1
memory_limit = 512M
post_max_size = 0
upload_max_filesize = 1000M

What's the problem? Uploading files less than 1MB is successful but anything greater than that, Google Chrome outputs:

Error 101 (net::ERR_CONNECTION_RESET): The connection was reset.

I already checked for the error log file but it doesn't exist in the directory. I also checked /var/log/httpd/error_log but no uploading related problems. I don't know anything else which might have caused the problem so I have reached out for your helping hand. Thanks!