nginx index directive works fine locally but gives 404 on ec2 - docker

Question

I have a web project that I want to deploy using docker-compose and nginx.
Locally, I:
docker-compose build
docker-compose push
If I docker-compose up, I can access localhost/ and get redirected to my index.html.
Now on my ec2 instance (a regular ec2 instance where I installed docker and docker-compose) I docker-compose pull, then docker-compose up.
All the containers launch correctly and I can exec sh into my nginx container and see there's a /facebook/index.html file.
If I go to [instance_ip]/index.html, everything works as expected.
If I go to [instance_ip]/, I get a 404 response.
nginx receives the request (I see it in the access logs) but does not redirect to index.html.
Why is the index directive not able to redirect to my index.html file?
I tried to:
Reproduce locally by remove all local images and pulling from my registry.
Kill my ec2 instance and launch a new one.
But I got the same result.
I'm using docker-compose 1.11.1 and docker 17.05.0. On the ec2 instance it's docker 17.03.1 and I tried both docker-compose 1.11.1 and 1.14.1 (Sign that I'm a bit desperate ;)).
An extract from my docker-compose file:
nginx:
image: [image from registry]
build:
context: ./
dockerfile: deploy/nginx.dockerfile
ports:
- "80:80"
depends_on:
- web
My nginx image starts from alpine, installs nginx, adds the index.html file and copies my conf file in /etc/nginx/nginx.conf.
Here's my nginx config. I checked that it is present on the running containers (both locally and on ec2).
# prevent from exiting when using `run` to launch container
daemon off;
worker_processes auto;
#
pid /run/nginx.pid;
events {
worker_connections 768;
# multi_accept on;
}
http {
##
# Basic Settings
sendfile off;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# SSL Settings
##
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
gzip_disable "msie6";
server {
error_log /var/log/nginx/file.log debug;
listen 80 default_server;
# root /home/domain.com;
# Bad developers use underscore in headers.
underscores_in_headers on;
# root should be out of location block
root /facebook;
location / {
index index.html;
# autoindex on;
try_files $uri #app;
}
location #app {
include uwsgi_params;
# Using docker-compose linking, the nginx docker-compose service depends on a 'web' service.
uwsgi_pass web:3033;
}
}
}
I have no idea why the container is behaving differently on the ec2 instance.
Any pointers appreciated!