Membership 2 Pro new members with subscriber role can't access BuddyPress members page

I've set up a basic WordPress site with Membership 2 Pro and BuddyPress (neither of which I've used before) and I'm testing what users can see.

When I create a new user and add them as a member to my membership, they appear in the list of members. The get assigned the role of subscriber.

When the user is logged out and they try to access the /members page, provided by BuddyPress - they get the correct 'protected content' message and offered to sign in.

When the user is logged in and they try to access the same page, they get a generic 'protected content' message, and I can't see what's preventing the user from accessing the page.

With another user, if I change their role to Editor they can see the page fine, but I don't want all members to be Editors. Normal members should be Subscribers.