The error message "504 Gateway Timeout nginx/1.18.0 (Ubuntu)" suggests that Nginx, running on Ubuntu, is acting as a proxy server and is timing out while trying

The error message "504 Gateway Timeout nginx/1.18.0 (Ubuntu)" suggests that Nginx, running on Ubuntu, is acting as a proxy server and is timing out while trying to connect to the backend server. The SSL cert is on the proxy server.