Something is blocking email coming from one source only (literotica.com).
Does Norton do this and if so what does it do with the blocked email?
Norton programs do scan emails, but they scan to check for malware. Most likely, it would be blocked by your ISP or email program. It might be in a Spam Detector some place. Norton could also put it in a Spam folder if you have that feature turned on.
Have a Good Night and
What email client are you using? Or are you using a web based email?
Check with your email provider. They may block emails from adult sites. Norton does not block email. It can only mark emails as spam if you have that set up.
Looks like we overlapped.
Thanks for comments and advice.
ISP denies responsibility. I found one quarantined email in Mallwarebytes but since freeing up that the problem persists.
Problem not yet solved.
And what email client are you using? That could be filtering your emails.
Have you checked your spam/junk folders?