Emails Blocked

How do you know this?  Did the sender get a message?  What was that message?

The sender has sent emails to me, but I never get them.  No message that I know of.

There are multiple reasons why you might not see a message someone said they sent you, the most common:

1) It got auto-filed by rules in your mail software

2) It got auto-filed in a junk mail folder by the mail server

3) It got dropped as SPAM by the mail server

4) It got blocked on deposit from the sending mail server

5) It was never sent to your e-mail address (typo, negligence on the sender...)

At this point, I really don't know which it is.