Keep getting 500 error after enabling SSL

I spun off a new droplet & migrated the DNS. The website worked fine, went ahead and added SSL from Lets Encrypt following the steps here: https://www.digitalocean.com/community/tools/nginx

Managed to successfully follow all the steps, but now my website keeps giving an HTTP 500 error ->

rewrite or internal redirection cycle while internally redirecting to "/index.nginx-debian.html", client: 49.207.200.121, server: www.epichiringcourse.com, request: "GET / HTTP/2.0", host: "www.epichiringcourse.com"

My conf file for the same:

server {
    listen                  443 ssl http2;
    listen                  [::]:443 ssl http2;
    server_name             www.epichiringcourse.com;
    set                     $base /var/www/epichiringcourse.com;
    root                    $base/public;

    # SSL
    ssl_certificate         /etc/letsencrypt/live/epichiringcourse.com/fullchain.pem;
    ssl_certificate_key     /etc/letsencrypt/live/epichiringcourse.com/privkey.pem;
    ssl_trusted_certificate /etc/letsencrypt/live/epichiringcourse.com/chain.pem;

    # security
    include                 nginxconfig.io/security.conf;

    # logging
    error_log               /var/log/nginx/epichiringcourse.com.error.log warn;

    # index.html fallback
    location / {
        try_files $uri $uri/ /index.nginx-debian.html;
    }

    # additional config
    include nginxconfig.io/general.conf;

    # handle .php
    location ~ \.php$ {
        include nginxconfig.io/php_fastcgi.conf;
    }
}

# non-www, subdomains redirect
server {
    listen                  443 ssl http2;
    listen                  [::]:443 ssl http2;
    server_name             .epichiringcourse.com;

    # SSL
    ssl_certificate         /etc/letsencrypt/live/epichiringcourse.com/fullchain.pem;
    ssl_certificate_key     /etc/letsencrypt/live/epichiringcourse.com/privkey.pem;
    ssl_trusted_certificate /etc/letsencrypt/live/epichiringcourse.com/chain.pem;
    return                  301 https://www.epichiringcourse.com$request_uri;
}

# HTTP redirect
server {
    listen      80;
    listen      [::]:80;
    server_name .epichiringcourse.com;
    include     nginxconfig.io/letsencrypt.conf;

    location / {
        return 301 https://www.epichiringcourse.com$request_uri;
    }
}

I have also confirmed that var/www/html/index.nginx-debian.html exists!

Not sure, what I am missing.