The above plugin will help us to investigate whether the mails are being sent or not (vs. being sent but not arriving to your inbox).
If you submit a form that should trigger a notification, you should see a record of the sent email in the mail log. (Toolset notifications are built on top of standard WP emailing.)
If you see the email log entry with above email log plugin that means emails are working but somehow its not sent by server. Maybe you will have to setup SMTP for the same and you can try to search for SMTP plugin and configure SMTP settings accordingly and then check if you able to see the mail in your inbox.
Hello Minesh. WP Mail Logging definitely helped. I was able to identify the issue is with my SMTP service. I need to reconfigure some DNS for notifications to work with my subdomain, transmissions.boomrattleboom.com