When you create a form to collect email subscribers:
If the person fills in the email and subscribes, he will never see this form again.
If the person doesn't fill in the email, just close the popup, he will not see this form again during this visit. But, if he visits your website one hour later, would you like to display the form to him again? If yes, maybe he will feel annoyed. You need to take this seriously.
If the person directly closes the form without being converted, we have 2 suggestions: