It means that Google found a link (could be a page, form, image, etc.) that they think you want to show up in search results, but your robots.txt is prohibiting them from doing so. You’ll need to log into the Google Search Console and click on your Messages to see which URL is being flagged. Then, check your robots.txt file (you’ll need to FTP into your site - it will be at the root level) and delete the URL if it’s there. If you want the URL to be hidden from search results (there are perfectly valid reasons for doing so, such as a pop-up form that you don’t want people to stumble upon), then leave it as is in the robots file and also ensure it’s not showing up in your sitemap.xml file.
Hope this helps, Dave