✔ 最佳答案
個人所知
yahoo mail冇得查收件人是否開啓,只有,你打錯收件人個mail,佢就會話給你知
Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following
addresses.
This is a permanent error; I've given up. Sorry it didn't work out.
但,不會查對方有冇開過
outlook就可以
去工具,選,
要求讀取回條(T)
咁就得