My robots.txt is not found (404) is this bad? Is Defender causing this?

When looking at my site on Google Search Console, on the "robots.txt Tester page, it's telling me that my Robots.txt is not found (404). I'm just wondering is the WPMU Defender plugin or Hummingbird causing this? Is this happening because of the plugins security?
Is it bad that Google Search Console can't find my robot.txt?

Thanks for any help :slight_smile: