This feature is essentially designed to make sure that your Recruiters and Sourcers inadvertently do not reach out to a candidate who are working with a current or an old client.

To enable this, all you have to do is go to Blocked Companies under settings,

and then mention the name of the company and their domain under the name and domain column.

Once you add the name and the domain which you want to prevent your Recruiters and Sourcers to reach out, you can click on ADD.

This would ensure that moving forward if someone from your team sources a candidate who works at this company or the e-mail has this domain, the user would see a little symbol right next to the candidate's name, once they open the profile.

If you hover over this symbol, a pop-up would show up which says 'This candidate is blocked since they work at Company name (Domain name)'