通过nginx反向代理时，PHP不会执行

Question

I am reverse proxying traffic on port 443 through nginx to my apache server, running on port 8080. If I access the phpinfo() file directly through port 8080, the php executes, but if I access it through port 443, I get the plain file download of the PHP file. How do I get the php to execute when it's accessed through the reverse proxy?

nginx server block

server {

  listen 80;
  listen [::]:80;

  server_name cloud.foo.com;

  return 301 https://$server_name$request_uri;

}


server {
  listen 443 ssl;
  listen [::]:443 ssl ipv6only=on;

  server_name cloud.foo.com;

  ssl_certificate /etc/letsencrypt/live/cloud.foo.com/fullchain.pem; # managed by Certbot
  ssl_certificate_key /etc/letsencrypt/live/cloud.foo.com/privkey.pem; # managed by Certbot
  include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

  location / {
    proxy_pass         http://127.0.0.1:8080/;

    proxy_set_header   Host             $host;
    proxy_set_header   X-Real-IP        $remote_addr;
    proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
    proxy_pass_header  Authorization;
  }

}

apache2 virtual host config

Listen 8080

<VirtualHost *:8080>

    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>