Solved this by further configuring the Nginx server. Edited the file located at /etc/nginx/sites-available/cms.eminenceconstructionlv.com.
The location object had try_files $uri $uri/ =404; by default. Replaced this with the following:
proxy_pass http://localhost:1337;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;