Email notifications not working reliably.

We have been having the same issue and I've even gone so far as to white list by return-path and create a dedicated SMTP account and it seems the actual sending side isn't working very reliably.

What is the form you are having the notifications issue with? Did you check your spam folder? You can also check if the recipients are in bounce list: https://www.jotform.com/help/262-How-to-Remove-Your-Email-Address-from-Bounce-List