Some form email responses are not delivered

We have created a Job Application form and assigned it a particular email address to send response notifications to, but are intermittently receiving those responses. We are not receiving them at 100%. Any help here would be appreciated. 

Thanks. 

Thank you for contacting us.

Could you please flag some entries which were not emailed on Submissions page?

Then, get back to us so we will be able to check the mail logs.