Looks like your site is using a lot of server's resources. You will need to optimize your website to use less resources. You can analyse your web access logs and restrict access for unwanted visitors and close some large threads on your application from public access if possible. If you have multiple domains under the same account, you can create them as separate cPanel accounts. Inorder to protect your websites from bad bots, you can enable CloudFlare from cPanel and then bots requests will be stopped.
If your application uses plugins and themes remove the unneeded ones. Also update your software to latest one (because, usually outdated software has resource usage problem).