This could be a spam blocker that classified your emails are spam and stopped them.
When your emails stop working, not only does it affect your customers
orders as expected, but you are
First: Test your WordPress install is actually sending emails
You will need an email provider. Such as the email that comes with your web hosting account a provider like Gmail. You'll also need to find your ...
spam blockers cause email to not be delivered
Steps to keeping your WooCommerce emails out of people's spam folders,
Check WooCommerce email settings; Check if your emails are going to Spam; Use an email with a different domain as your
The most common reason for emails going missing is that your WordPress hosting
Seems perhaps the anti-spam plugins aren't doing their job then.