Let’s start the discussion about Rails server is already running [ Solved ] in following methods.
Rails server is already running
The error occurs because the PID is stored in a file, the web server assumes that if that file exists, the process is already executing. Normally, when a web server is closed, that file is erased; but, in rare circumstances, correct deletion does not occur, and you must manually remove the file.
To locate and terminate a process based on the port number on which it is running. Replace 8000 with the port on which your software is running.
sudo kill -9 $(lsof -i :8000 -t)
I hope the strategies listed above work for you. Happy coding and come back again.