Lighttpd PHP File Upload - Error 413 request entity is too large

I'm having problem with PHP File upload running on lighttpd web server deployed on my VortexSX86. Lighttpd keep giving me the 413 error message ( 413 request entity is tool large)

Open /etc/lighttd/lighttpd.conf change the following parameters :

server.max-request-size=100000000     # or whatever you want max file size to be
server.upload-dirs=( "/mnt" )     # location to place the uploaded file
                               # probably should be the same as php.ini
server.network-backend="write"    # this one was the key one for me

if the value of "write" doesn't work, try "writev".

server.network-backend="write" or server.network-backend="writev"

Make sure the upload directory is exist and writable.
Done.