Happy to help resolve this for you. Can you DM me the email address you have set to receive email notifications?
I can white list that email on our end to ensure emails aren’t being blocked over here.
Can you also please try whitelisting the email address: email@example.com on the email accounts where you’re not receiving the form submission emails & then perform a test again (using a placeholder email address of firstname.lastname@example.org, something other than your own email address)?
Here’s a resources that shows how to whitelist an email address on your account: http://www.whatcounts.com/how-to-whitelist-emails/