Mailer-daemon messages from Yahoo mean that an email being sent to or from a Yahoo.com email address have encountered an error that prevented them from reaching the intended address. You could be receiving a mailer-daemon email because of things as simple as a typographical error to things as detrimental as a compromised account. The purpose of the mailer-daemon message is the similar to a “receipt confirmation,” but tells you something has gone wrong instead of right. Writer Bio
