We are aware some users are experiencing issues accessing their Yahoo Mail using third-party mail clients. Removing and re-entering your Yahoo Mail password in the email client should solve this. Read our help article for more information and steps. You may also access Yahoo Mail on the web at mail.yahoo.com or using the Yahoo Mail app for iOS or Android.

Email "Failed Delivery" message

When you get mail from a "MAILER-DAEMON" or a "Mail Delivery Subsystem" with a subject similar to "Failed Delivery," this means that a message you sent was undeliverable and has been bounced back to you. These messages are produced automatically and usually include a reason for the delivery failure.

Failed or "bounced" messages normally consist of two parts:

  1. The reason for the bounce
  2. Your original message.

Example failure notice

Hi. This is the email-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.

123.45.67.89 failed after I sent the message.
Remote host said: 554 delivery error: dd This user doesn't have a yahoo.com account (testing123@yahoo.com) [-5] - mta123.mail.mud.yahoo.com

--- Below this line is a copy of the message.

Return-Path:
Received: (qmail 24519 invoked by uid 60001); 11 Nov 2010 15:37:25 -0000
...
...
X-Mailer: YahooMail/11.4.9 YahooMailWebService/0.8.107.285259
Date: Thu, 11 Nov 2010 07:37:24 -0800 (PST)
From: Yahoo Customer Care
Subject: Test Message
To: testing123@yahoo.com
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="0-162906830-1289489844=:24510"

--0-162906830-1289489844=:24510
Content-Type: text/plain; charset=us-ascii

[Text of the original message here]

--0-162906830-1289489844=:24510--

The most common reason for a failed delivery is that the email address you entered isn't valid. If the Mailer Daemon says that the account doesn't exist, double-check the spelling of the address you entered. A single misplaced letter can be enough to cause a failed delivery. If the message continues to be bounced back to you, you might want to verify that the account hasn't been closed or moved.

If you are getting a failed delivery message for each incoming email you receive this could indicate the presence of a non-functioning forwarding address. Please check your mail settings for a forwarding address that needs to be updated or deleted. If you find one you do not recognize please review all of your mail settings too.