I’ve isolated the source of the problem to the “BuddyBoss” plugin. It is built on the BuddyPress framework. So I’ll see what I can find out about how it controls admin toolbar access and what I need to change. Any suggestions would be welcome.
Also, is there a way to direct the “membership_manager” to the frontend of the site (which will have the toolbar available, rather than the WP Admin backend?
