Postgresql 10.x installer configures password wrong? (Windows)
If you are using the EDB installer, when it asks for a password, that is the password for the PostgreSQL user named postgres, not for the user named tom.

Perhaps there is a way to make our 3rd party app connect as postgres?

Or if you want it to use the database role whose name matches your Windows account name, you should be able to connect with

psql.exe -U postgres postgres


And then:

create user tom with password 'hi tom';