It tells you in the report.
If you compare the list of blocked files to your robots.txt you will see these two rules match:
Disallow: /wp-content/plugins/
Disallow: /wp-content/cache
You can either remove them two rules or create specific allow rules for those directories – for example this will allow the first blocked directory to be accessed….
User-agent: *
Allow: /wp-content/cache/minify/
Add more Allows for each blocked directory.