BuddyPress Social theme with Membership plugin does not work on iPhones

I just spent several days switching my website from the Business Portfolio child theme to BuddyPress Social child theme.

I am using WPMU multi site with the membership plugin and BuddyPress plugin.

Everything looked wonderful until I started getting e-mails from my members who were using iPhones to access the site. They are able to sign in but the menus are not visible, but they do have some sort of drop down menus, but they do not work.They cannot get to any of the pages.

I can't test this as I do not have an iPhone.

Does anyone have any information or help with this?

Thanks