An error in robots.txt can cause Google to stop crawling a section of your site. In such case it is good to update and resubmit you robots.txt to Google proactively. Assuming that you have owned your website in Google search console, here are the steps to resubmit your site.
- Click on Crawl > robots.txt Tester in Google search console (webmaster tools).
- Click on Submit button below the robots.txt file text area.
You see a popup as shown below with few options. Click on submit button next to “Ask google to update”.
- After sometime, check robots.txt in Tester page again. You should be able to see updated robots.txt.