Hi, I'm writing this after almost 30 minutes looking into this problems, just to know it was an easy fix.
So... Let's go!
The problem was when learning about creating a back-end server, at some point it says to create a new database with the name that you used in the orm. The command used in the video to create was
createdb server_name, but it gave a problem about password in my windows 10 machine.
The problema was the following:
createdb testdatabase createdb: error: connection to server at "localhost" (::1), port 5432 failed: FATAL: password authentication failed for user "<username_placeholder>"
So after around 30 minutes investigating I discovered that was symply about the command used.
The right command is the following:
createdb -U postgres testdatabase
Hope it answer your search to solve it. Also, hope you don't lost 30 minutes searching!