The Cannot Open Display error can occur on a Linux system when trying to open a GUI application, especially if opening it from the command line. It can also pop up if you are trying to use X11 forwarding via SSH to a remote system. The good news is that this error is relatively easy to fix, whether you are getting it when accessing a local application or a remote server. In this tutorial, we will cover the steps necessary to fix the Cannot Open Display error on Linux.
This is a companion discussion topic for the original entry at https://linuxconfig.org/fixing-the-cannot-open-display-error-on-linux