Please follow the next steps in order to solve this issue:
- Make sure that you have administrator rights, because the settings page is visible for administrators only.
- If you are using multisite: If the plugin is activated on network, the access to the settings page is permitted from every sub site and is not permitted from the main multisite admin panel.
- It is possible that you have a another security plugin installed, that affects the user access rights. Please try to deactivate the rest of the plugins one by one and check if the problem still remains.