I first installed Multisite plugin:
That worked perfectly.
But at that time I didn't check if CMS editor was working or not.
Along with that I installed TailwindCSS Boiler plate:
And used its commands from SSH those which were provided in that theme's description below:
Launch a terminal from the romainmazb-tailwindcss-boilerplate directory
Run npm install to install the boilerplate dependencies.
Then go to the blank-src directory and launch again npm install, this will install your theme dependencies, for now just the ones required by October, PostCSS and TailwindCSS.
Go back to the romainmazb-tailwindcss-boilerplate directory and run npm run watch` to run the development server with hot reload.
Since a new blank theme were created, go to the October backend settings and activate your new theme.
After that the editor gave this error.