Good afternoon Kelsey and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the emails not being systematically received.
I would love to help you with this topic.
What is going on is that by default all event related emails are being sent by the built-in WordPress mail system. Sometimes, that means that some of these will get blocked.
The most popular solution to circumvent this would be to install and configure a plugin that sends emails through a normal SMTP server.
I personally like the following one (it even offers a testing tool): https://wordpress.org/plugins/easy-wp-smtp/
Let me know if that helps.
Have a great day!
Geoff B.