Mod PageSpeed
The PageSpeed Module, also known as mod_pagespeed, is a server module that performs various file optimizations similar to WP Rocket's. These can conflict so mod_pagespeed should be disabled when using WP Rocket.
If you are running Amazon Lightsail, the Bitnami stack has mod_pagespeed enabled by default. To disable it, please follow the steps provided in this Bitnami documentation: Disable PageSpeed
For any other server environment, please contact your host or server admin to ask them to disable mod_pagespeed.