Unknown directive in NGINX default.conf - nginx

Question

I accidently deleted my default.conf file. Luckily, I copied and pasted the original text into another file. My problem is, when I try to start NGINX after creating a new default.conf file and pasting in the text using nano editor, I get the following error:
unknown directive " " in /etc/nginx/conf.d/default.conf:3
I suspect the pasted text is injecting some unneeded stuff. If I'm correct, how do I identify that and clear it out?
Here's what I'm adding to the default.conf file:
server {
#listen 80;
server_name xr7tsi.com www.xr7tsi.com;
access_log /home/ubuntu/client/server_logs/host.access.log main;
location / {
root /home/ubuntu/client/build;
index index.html index.htm;
try_files $uri /index.html;
add_header X-Frame-Options SAMEORIGIN;
add_header X-Content-Type-Options nosniff;
add_header X-XSS-Protection "1; mode=block";
add_header Strict-Transport-Security "max-age=31536000; includeSubdomains;";
}
large_client_header_buffers 4 64k;
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
server_tokens off;
location ~ /\.ht {
deny all;
}
location /api {
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $http_host;
proxy_pass http://127.0.0.1:5000;
}
listen [::]:443 ssl ipv6only=on; # managed by Certbot
listen 443 ssl; # managed by Certbot
ssl_certificate /etc/letsencrypt/live/xr7tsi.com/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/xr7tsi.com/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}
server {
if ($host = www.xr7tsi.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
if ($host = xr7tsi.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80 default_server;
listen [::]:80 default_server;
server_name xr7tsi.com www.xr7tsi.com;
return 404; # managed by Certbot
}