Message Delivery Delay

Message Delivery Delay

If you send mail to yahoo.com and received the mail return from server. With this show topic "Message Delivery Delay"

If you send mail to yahoo.com and received the mail return from server -> show topic "Message Delivery Delay"
It shows detail as follows
421 Resources temporarily unavailable. Please try again later
421 Resources temporarily unavailable. Please try again later

Note. The Yahoo! Mail MTAs are temporarily too busy. Your server should try to resend the message after a few minutes.
Our mail server will send this email again but receiver will get it later.