Eu também tive o problema a 403, que foi causado pelo modo de diretório.
Eu configurei o diretório raiz em casa, e o modo padrão para o diretório inicial é 600.
Então eu encontrei este artigo link , e tentei mudar o diretório raiz para 755, e o problema foi resolvido.
So it seems that the default permissions on user home directories in
Ubuntu 12.04 is 700.** Nginx needs to have read permission the files
that should be served AND have execute permission in each of the
parent directories along the path from the root to the served files.**
You can give your user directory these permissions by running
chmod 701 user_home
You may also use 755, which is the default
permission setting on the home directory on many systems.
The directories/files in your web root can belong to the www-data user
or your regular personal user as long as the user/group that nginx
runs as (as defined in nginx.conf) has READ permission on all files to
be served and execute permission on all web root directories.