I think there are some more modern caching plugins that can handle caching for logged-in users, and I believe some of those will also help mitigate Varnish caching in those circumstances.
But the big problem is that almost by-definition membership plugins either shouldn’t be cached or else they should be cached very carefully. In the simplest case without membership-aware caching either non-members can see members-only content, or else members will see cached non-member content. In worse cases the site may load incorrect scripts based on the wrong assumptions about what is and isn’t cached.
I’m pretty sure WP-Rocket has automatic and/or manual configuration settings for the major membership plugins. I’m not sure about really old-school membership plugins like s2Member. More likely you’re going to have to turn off Varnish or at least write exceptions for membership-related pages.
I think there are some more modern caching plugins that can handle caching for logged-in users, and I believe some of those will also help mitigate Varnish caching in those circumstances.
But the big problem is that almost by-definition membership plugins either shouldn’t be cached or else they should be cached very carefully. In the simplest case without membership-aware caching either non-members can see members-only content, or else members will see cached non-member content. In worse cases the site may load incorrect scripts based on the wrong assumptions about what is and isn’t cached.
I’m pretty sure WP-Rocket has automatic and/or manual configuration settings for the major membership plugins. I’m not sure about really old-school membership plugins like s2Member. More likely you’re going to have to turn off Varnish or at least write exceptions for membership-related pages.