Discourse runs inside a Docker container, which is essentially like a virtual machine. All components are self-contained so it is rather difficult to lose anything. To see the logs that the NGINX server produces, such as access and error, you’ll need to go to the logs folder inside the container’s shell.
Exercise caution while inside the shell, as this can break your instance.
Enter your container’s shell using these commands. You can skip su - if you’re already root.
su -
cd /var/discourse
./launcher enter app
cd /var/log/nginx
Open the file error.log in your preferred terminal text editor (I prefer nano only because I’m not an expert, you’ll need to install it first).
nano error.log
Locate the last line (the latest entry) of the file by pressing ^V (CTRL-V). When finished, press ^X to return to shell.
When finished, run exit to return to your CentOS root shell.