Error (jedi): Failed to start Jedi EPC server.

Error (jedi): Failed to start Jedi EPC server.
*** You may need to run "M-x jedi:install-server". ***
This could solve the problem especially if you haven't run the command yet
since Jedi.el installation or update and if the server complains about
Python module imports.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
https://github.com/tkf/emacs-jedi/issues/140

Please explain why you don't understand jedi:install-server and why you think creating the directory solves the problem. It is VERY important to have a clear document so that we don't need to deal with questions.
Let me add more explanations.
Running jedi:install-server installs Python modules required by Jedi.el. You just need to type M-x jedi:install-server RET to install or update the Python modules. To make this command to work, you need an Emacs package called python-environment.el and Python command line program called virtualenv. We have jedi:install-server to solve dependencies outside of Emacs packaging system. This cannot be integrated with, for example with package-install command since Emacs packaging system does not allow us to install Python packages at the install time. The command jedi:install-server makes Python virtual environment in ~/.emacs.d/.python-environments/default/ and install all Python modules required by Jedi.el in it. This way, you don't need sudo or su to install anything and it is easy to install compatible Python packages.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 https://realpython.com/blog/python/emacs-the-best-python-editor/#installation