Robots blocking Googlebot

Hi,
When using Fetch and Render tool in Google search console some scripts and images were found to be blocked by robots.txt file of my website when Googlebot tried to reach them. It is to mention here that my robots.txt file doesn’t contain any code. Its a blank file. I couldn’t find why it’s happening so. Can anyone help me out! It is to be noted here that I am using Yoast SEO, Wordfence security, WP Super Cache and Cloudflare CDN free subscription.