Infinite SEO - unable to toggle between yes and no

I've just started using the Infinite SEO plugin and I've encountered a problem.

I'm unable to toggle between yes and no on the network admin settings page. (were it says: Show this to Site Admins)

When I toggle "yes" and save, the page is refreshed and "settings saved" pops up. then when I look at the radio buttons, "yes" is selected but not when I navigate to another page and back again it is reset to "no".

Therefore I am unable to use this pages in the child-sites as I'm told that the admin has prevented acces to these pages.

more info:
I did not realize the first time that I had to define sitewide in my config.php file, so the plugin has been reinstalled a couple of times during my trubleshooting. But now the plugin works, and I am able to see the first two pages (as for some reason they work) but not the rest in the child-sites settings.

Thanks in advance.