postgres 12 password failure port 5433

Hi,
I have postgres 10 running on 5432 and pgadmin is connecting ok.

I have just installed postgres 12 on ubuntu 18.04 using apt-get install
I have the following success messages (see below)
I have verified that I have a database running at 5433 programmatically.
The PGADMIN4 "postgres admin tool" is giving an error "UNAUTHORISED message
(see below)
WHEN i TRY TO LOGIN USING PSQL CONSOLE using command line
psql -U postgres -p 5433 -h localhostI get an password error message
psql: error: could not connect to server: FATAL: password authentication
failed for user "postgres"
FATAL: password authentication failed for user "postgres"

Unauthorized

The server could not verify that you are authorized to access the URL
requested. You either supplied the wrong credentials (e.g. a bad password),
or your browser doesn't understand how to supply the credentials required.

Success. You can now start the database server using:
pg_ctlcluster 12 main start

Ver Cluster Port Status Owner Data directory Log file
12 main 5433 down postgres /var/lib/postgresql/12/main
/var/log/postgresql/postgresql-12-main.log