Did you close the tutorial or vscode and try to reopen and continue @venkateshrnaik?
Your best bet is to finish a tutorial in one session. Closing it and trying to reopen and continue can have issues sometimes. If you ls -a in the terminal there, and don’t see a few folders - you will likely need to start over, unfortunately. If you do see the folders, there’s a series of commands that run when you initially load a tutorial, that don’t get run when trying to continue. I will try and fix this. If you see those folders, you could try running all those commands (line 5-17) in the terminal and see if you can continue from there.
Edit: actually, I think you only need to run the last one - sudo service postgresql start, then you can try logging in again and continuing.