I used this statement to change the postgres role permissions:
ALTER ROLE postgres WITH NOLOGIN.
I have only one role: the postgres default role. Sorry for my stupidity. Now I can't login anyway to the DB. If I try to connect to the DB tha answer is:
C:\>psql -h 192.168.167.31 -U postgres
Inserisci la password per l'utente postgres:
psql: FATALE: al ruolo "postgres" non è consentito effettuare il login
runas?