I don't seem to be getting emails anymore when somebody submits a form

Just got a call today from somebody who said they submitted a form 2 days ago. I never got the "Notification" email. I checked the JotForm program and saw the submission there. Please advise if I need to do something different. 

I checked your account email history and did not see any issues with sending from our end. 

https://www.jotform.com/help/293-How-to-View-All-Your-Form-Email-History

Check your spam/junkmail folder to see if the emails were filtered there.