The error is thrown from nginx. check nginx error log for details.

Thanks, where would I find this file on Mac OS? Or can I view it in Terminal with a command? I've had a Google but I can't find anything that works. A search for nginx on my computer doesn't find anything that looks like it's what I need - that's with hidden files set to display too.

I'm not sure, i don't use mac. If you're running vagrant or linux probably it's in /var/log/nginx/error.log

In /etc/nginx/sites-enabled/ I found this, if it helps?

server { listen 80; listen 443 ssl http2; server_name MYPROJECTNAME.dev; root "/home/vagrant/Code/MYPROJECTNAME/public";

index index.html index.htm index.php;

charset utf-8;

location / {
    try_files $uri $uri/ /index.php?$query_string;
}

location = /favicon.ico { access_log off; log_not_found off; }
location = /robots.txt  { access_log off; log_not_found off; }

access_log off;
error_log  /var/log/nginx/MYPROJECTNAME.dev-error.log error;

sendfile off;

client_max_body_size 100m;

location ~ \.php$ {
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_pass unix:/var/run/php/php7.1-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;


    fastcgi_intercept_errors off;
    fastcgi_buffer_size 16k;
    fastcgi_buffers 4 16k;
    fastcgi_connect_timeout 300;
    fastcgi_send_timeout 300;
    fastcgi_read_timeout 300;
}

location ~ /\.ht {
    deny all;
}

ssl_certificate     /etc/nginx/ssl/MYPROJECTNAME.dev.crt;
ssl_certificate_key /etc/nginx/ssl/MYPROJECTNAME.dev.key;

}

I've tried a few different websites in my "Sites" folder. Does the site NEED a database and/or .php files to work or would an index.html get picked up too? Also should there be a public folder or should having an index.html file as a direct child work fine as well?

EDIT Not sure what's going on with the code formatting on this forum. I haven't even used any tags here and it's formatting it like this?!