Email deliverability depends on multiple factors. While email itself should be valid in order to get your delivered in first place but your domain health also plays an important role.
EasyLeadz gives an accuracy of over 95% for the emails. It automatically skips unverified and catch email addresses.
What is a catch all email address?
A catch all email or domain is the one where the domain owner has set to accept or catch all emails instead of only on valid emails. In short, there is no certain way to verify whether the email that is on catch domain is valid or not. That's why we skip those domains.
What is domain health?
If you have been sending too many emails in past and have been using junk data or too many bounces than your domain health is at stake. All spam monitoring websites will put you in their global spam lists and your future emails will start getting into SPAM or outrightly rejected by servers thus leading to more bounces.
So don't send emails on junk and unverified data and don't spam people. Give them a choice to opt out from your email campaigns. Respect that opt out.
It may be a case that the email that you reaching out is valid but you are getting bounce response because of your domain health.