I created a user for my bbPress forum and I could login as this user in bbPress, but not in WP. After I checked (logged as admin in WP) the account of this user in WP blog, I saw that it has no role. So in bbPress settings I set the correspondance between WordPress role and bbPress (Settings->WordPressIntegration menu). And problem was solved. Now each user that is registered through bbPress can loggin in WP.
Maybe this will help.
I created a user for my bbPress forum and I could login as this user in bbPress, but not in WP. After I checked (logged as admin in WP) the account of this user in WP blog, I saw that it has no role. So in bbPress settings I set the correspondance between WordPress role and bbPress (Settings->WordPressIntegration menu). And problem was solved. Now each user that is registered through bbPress can loggin in WP.
Maybe this will help.