I hope you are well today and thanks for posting here.
You said contact form is working but not the main application website and you are not getting any email from contact form.
So please tell me when you say contact form is working then what is exactly working in it and what are you referring as application website?
It doesn’t happen usually so we don’t know the exact reason. This can be due to the server issue where you have hosted your site so please contact your web host or check error logs as described on the following pages to know the reason of issue.