FYI for anyone who finds this topic from a google search:
The reason you can’t delete the bbp_keymaster role is that it’s currently assigned.
Dashboard > Users:
Scroll through and see which user(s) has/have the role assigned.
Select the check box for the user(s) with the bbp_keymaster role assigned and use the “Grant Roles” button at the top of the section to uncheck the keymaster role.
After that you should be able to delete the role.
