Are you still seeing this @cjrw42? Several users were having issues recently, but those problems should be fixed now. This may have been related and may also fixed. Let us know if you are still stuck.
~/project$ psql --username=freecodecamp --dbname=worldcup
psql: error: connection to server on socket “/var/run/postgresql/.s.PGSQL.5432” failed: No such file or directory
I’ve seen that one a few times now recently. In the practice projects, the reset button should set that stuff back up for you. It isn’t implemented in the cert projects. It seems to occur frequently enough that I will file an issue and make a fix for it. For now, you should be able to enter these commands to set it back up manually