Hi @martinbraun, the common case would be cache plugins cause RSA to not work. I will test WPFC with RSA to see if I can reproduce your issue. In the meantime, you can check the FAQ section of the RSA page for more information about cache plugins:
Most commonly, Restricted Site Access is not compatible with some page caching solutions. While the plugin hooks in as early as it can to check visitor permissions, its important to understand that some page caching plugins generate static output that prevents plugins like Restricted Site Access from ever checking individual visitors.
To the extent that sites blocked by this plugin should not need to concern themselves with high scale front end performance, we strongly recommend disabling any page caching solutions while restricting access to your site. Keep in mind that most page caching plugins do not cache the “logged in” experience, anyhow. Also note that the plugin is fully compatible with other caching layers, like the WordPress object cache.
