The project's custom PostCSS configuration attempts to configure unnecessary plugins:
- postcss-modules-values
- postcss-modules-scope
- postcss-modules-extract-imports
- postcss-modules-local-by-default
- postcss-modules
Remove the plugin specified in the error message from your custom PostCSS configuration.
CSS Modules are supported in Next.js' built-in CSS support. You can read more about how to use CSS Modules here.