Assignees not receiving email notifications

[hdi_kwilliams]

I have several users who don't receive emails from tickets they are assigned to. This happens on ticket creation or when a ticket is given to them. I've checked all their permissions and everything is a green. I literally assigned a ticket to a user 30 mins ago (5:15pm CST) and the user did not get a notification.

Could there be some type of block as mentioned in this ticket?
https://community.atlassian.com/t5/Jira-Software-questions/Not-receiving-email-notifications/qaq-p/1672564