Failed to start high performance web server and reverse proxy server nginx

UPDATE - I got these error logs:

nginx: [emerg] unknown "request_url" variableAug 19 01:14:58 nginx[4890]: nginx: configuration file /etc/nginx/nginx.conf test failed

Here is my nginx.conf file:

user www-data;worker_processes auto;pid /run/nginx.pid;include /etc/nginx/modules-enabled/*.conf;events {    worker_connections 768;    # multi_accept on;}http {    ##    # Basic Settings    ##    sendfile on;    tcp_nopush on;    tcp_nodelay on;    keepalive_timeout 65;    types_hash_max_size 2048;    # server_tokens off;    # server_names_hash_bucket_size 64;    # server_name_in_redirect off;    include /etc/nginx/mime.types;    default_type application/octet-stream;    ##    # SSL Settings    ##    ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE    ssl_prefer_server_ciphers on;    ##    # Logging Settings    ##    access_log /var/log/nginx/access.log;    error_log /var/log/nginx/error.log;    ##    # Gzip Settings    ##    gzip on;    # gzip_vary on;    # gzip_proxied any;    # gzip_comp_level 6;    # gzip_buffers 16 8k;    # gzip_http_version 1.1;    # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;    ##    # Virtual Host Configs    ##

The "request url" part of the error could be in my sites-enabled/default file in the location block near the bottom:

server {    listen 80 default_server;    listen [::]:80 default_server;    # SSL configuration    #    listen 443 ssl default_server;    listen [::]:443 ssl default_server;    server_name         www.domainname;    ssl_certificate     /etc/nginx/ssl/server.crt;    ssl_certificate_key /etc/nginx/ssl/server.key;    ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;    ssl_ciphers         HIGH:!aNULL:!MD5;    #    # Note: You should disable gzip for SSL traffic.    # See: https://bugs.debian.org/773332    #    # Read up on ssl_ciphers to ensure a secure configuration.    # See: https://bugs.debian.org/765782    #    # Self signed certs generated by the ssl-cert package    # Don't use them in a production server!    #    # include snippets/snakeoil.conf;    root /var/www/html;    # Add index.php to the list if you are using PHP    index index.html index.htm index.nginx-debian.html;    server_name _;    location / {            # First attempt to serve request as file, then            # as directory, then fall back to displaying a 404.            try_files $uri $uri/ =404;            return 301 https://www.hobyn.co$request_url;

ORIGINAL QUESTION - I get the failed to start high performance web server and reverse proxy server when running:

sudo /etc/init.d/nginx restart

to restart nginx after making the server block configurations below to my /etc/nginx/sites-available/default file. My angular app is being served in /var/www/html:

server {    listen 80 default_server;    listen [::]:80 default_server;    # SSL configuration    #    listen 443 ssl default_server;    listen [::]:443 ssl default_server;    server_name         www.mydomainname;    ssl_certificate     /etc/nginx/ssl/****.crt;    ssl_certificate_key /etc/nginx/ssl/****.key;    ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;    ssl_ciphers         HIGH:!aNULL:!MD5;location / {            # First attempt to serve request as file, then            # as directory, then fall back to displaying a 404.            try_files $uri $uri/ =404;            return 301 https://www.mydomainname$request_url;    }