Email blocked by some addresses

Students fill out a form to sign up for classes. They use PayPal to pay. I have a notification set up to send the students their class information (Zoom link, etc). Some student receive the notification and some do not. The same students consistently report they didn’t receive the notification–it’s not in their spam folder. There is some similarity between the students who don’t receive the notification. They all have a / address. Is this an issue with my host? Or is there something I can do through Gravity Forms to make sure they receive the email notification? Or is this caused by a problem with their email account?

I recommend you analyze your email notification to see how spammy it looks. Every mail provider has a different idea of what looks like spam, and what will be blocked.

You can use this site to analyze one of your notifications:

Load that page in a browser. You will receive a unique email address. Copy that, and submit your form so that that is the email address to receive the notification. Leave that browser tab open while you test. After testing the form, refresh that page in a minute or so, and take a look at your score. In most cases I have seen, a score of 6.9/10 is pretty normal for shared hosting, and normally requires a DNS change. Check yours, and refer to the recommendations for things you can do to improve the deliverability.

Post your unique URL here (to the results page) if you need assistance interpreting the recommendations. Thank you.