Nginx not loading other sites after enabled SSL - ssl

Question

Here is my /etc/sites-available/default
server {
listen 443 default_server;
server_name _;
ssl on;
ssl_certificate /etc/ssl/certs/example/example.com.crt;
ssl_certificate_key /etc/ssl/certs/example/example.com.key;
root /usr/share/nginx/html;
index index.html index.htm;
location / {
try_files $uri $uri/ =404;
}
}
server {
listen 80 default_server;
listen [::]:80 default_server ipv6only=on;
return 301 https://$host$request_uri;
root /usr/share/nginx/html;
index index.html index.htm;
# Make site accessible from http://localhost/
server_name localhost;
location / {
try_files $uri $uri/ =404;
}
}
The first block is what I've added recently. I host multiple sub-domains on this server. This is an example of sites-available/my.example.com:
server {
server_name my.example.com;
access_log /var/data/log/nginx/my.example.com.log;
error_log /var/data/log/nginx/my.example.com.log;
root /var/data/www/lmy.example.com/htdocs;
index index.php;
location / {
try_files $uri $uri/ /index.php?$args;
}
location ~ \.php$ {
include fastcgi_params;
fastcgi_pass unix:/var/run/php5-fpm.sock;
}
}
Whenever I used to go to http://my.example.com, the website would load fine. But now, going to https://my.example.com just goes to the default page. The my.example.com file is symlinked from sites-enabled. The config seems fine, because if I comment the line return 301 ... from the port 80 block, http://my.example.com works again, but https://my.example.com shows the default nginx page.