Settings page returns “unautorized”

Hi,

trying to connect to PixProof settings page (/wp-admin/options-general.php?page=pixproof), I get an error message stating that I don’t have sufficient permissions.

I’m on a network/MU WP installation, with a super-admin account, I checked that I got all permissions (namely “manage_options”), tested on several websites on the network and even created a bare new admin account, it’s the same.