pgAdmin 4 Database lost after filed start-up - how do I recover the connection?

After a few months away from pgAdmin 4, I attempted to open the program - first time, it failed, second time it started up - but the database, called 'athome4' was missing. I checked in QGIS and the database and files still exist. So I would like to know how I can recover the connection to pgAdmin 4 so I can work with this database again. I simple step by step explanation would be best. I am very concerned that if I start work on a new project that this may happen again.