bbPress.org

Chances are you need to set the database host in the “advanced” settings. On the same screen as the database username, password and database name, there is a checkbox (IIRC) that says something like “advanced database settings” and checking that reveals the place where you enter the database host name.

I don’t agree that it’s an advanced setting, but if you have a database host name to use, that is where you enter it.