“Sorry, you’re not allowed to access this page” error
This is not something that could be triggered by WP Rocket.
You can verify that by enabling WordPress Debugger and see if there is anything related to WP Rocket showing here.
It usually affects access to other plugins as well. The common main cause is administrative privileges. But there could be other reasons why it's happening.
The following article explores all the potential reasons and solutions to fix it: