If you have searched around and can’t find the answer, read on.
If you are running Apache, and have Set PHP to run as FastCGI, this is probably your solution. The information below is specifically for Centos Plesk users. FcgidMaxRequestLen –>This is your problem. Before updating to the newest version, it was defaulted to 1gb. Now it is 128kb.
Quick fix if you are command line savy:
/etc/httpd/conf.d/fcgid.conf
FcgidMaxRequestLen 1073741824
/etc/init.d/httpd restart
You should now have no issues with new uploads in WordPress.