Hello, Everybody!

Many thanks for your responses! I appreciated your explanation about
inactivity of mailbox that means a user has not logged in to receive
mail in an extended periods of time. But that is strange. Because this
"bounced" subscriber has posted more than two messages on Sunday night,
again last night. It should not be an extended period of time that he
was inactive. I just don't understand why this bounced back to me.

Paul, that is OK. It just bounce one time, but not over 5 (five)
messages as undeliverable. It must be a rare occasion that my
subscriber's mail bounced back to my listserv.

Again, many thanks for your quick response!

Johnny :)