This issue for email is well documented within the forums. This is NOT a JM issue. 99.99% of the time it’s related to your hosting provider and how they manage the WP SMTP.
Refer to this thread. https://www.ads-software.com/support/topic/emails-not-generating-after-application-submission/
That means that the issue lies most likely with your web hosting provider.
You have several option in this case depending on the circumstances, and what email host you are using to receive your emails?
We use wpMandrill or SendGrid Mailer plugins and there are several SMTP plugins for WordPress, we used to use Postman SMTP Mailer but it’s presently removed from the rpository – hopefully it will be added back soon.
https://www.ads-software.com/plugins/sendgrid-email-delivery-simplified/
Also refer to these threads for similar details.
https://www.ads-software.com/support/topic/no-more-notification-emails
https://www.ads-software.com/support/topic/job-alerts-emails-not-send
https://www.ads-software.com/support/topic/email-notifications-not-sending
