Why is it that the mail transmission was successful on Naver mail, but it appears as not being read?

I sent an e-mail to Naver Mail.

1111 2018-02-10 Gentleman

No, that's not the case in the mail system.
If the other server doesn't give you a signal that you received it well even though you sent it, it says an error occurred.

Gentleman 7 years ago 0

A. 2

It won't happen unless the other person's mail server blows the mail
As far as I know, it appears that way because there is no way to check the other person's mail on Naver mail

Gentleman 7 years ago 0

A. 3

Not reading is meaningful in Naver, but it doesn't mean much if you send it to another mail service. It's not accurate.

Gentleman 7 years ago 0

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