※ 필수입력정보 ※

▷ 제품버젼 : nmail3.7

▷ 오류발생 메뉴/주소 :

"2014-11-21 13:24:47" [7280] "***-****-*******-****-****.eml""[MTA Connect Success] 220 *******************************************" [localhost]
"2014-11-21 13:24:47" [7280] "***-****-*******-****-****.eml""[MTA Helo Success] 250 OK" [localhost]
"2014-11-21 13:24:48" [7280] "***-****-*******-****-****.eml""[MTA MailFrom Fail] 550 5.1.8 envelope-from address(****@****) must exist." [localhost]
"2014-11-21 13:24:48" [7280] "***-****-*******-****-****.eml""[MTA Quit Success] (null)" [localhost]
"2014-11-21 13:24:48" [7280] "***-****-*******-****-****.eml""Send Return Mail" [localhost]

▷ 에러메세지 :

 550 5.1.8 envelope-from address(****@****) must exist." [localhost]

▷ 질문내용 :

메일 수신때 해당 리턴 메시지는 뭘의미합니까?