Cannot create database PostgreSQL [on hold]

Working with Ubuntu on a server. I installed PostgreSQL.
Baiscally I am following this tutorial.

I am logged in with my user accoung max. I logged into the PostgreSQL account from the bash prompt like so

sudo -i -u postgres

Worked!
Then I started PostgreSQL by typing

psgl

Worked!

Then I created a test database like so

createdb test

Worked!

Then I created a new user like so

createuser max
> superuser -> yes!

Worked!

Then I wanted to create a database with a matching name to the newly created user, so

createdb max

Did not work, nor threw an error.

When I check my databases with list (logged in as postgres) I do not see the database max.
How would I create the database max for max that I can logg in from the bash (unter the account of max) with psql?