There appears to have been an incident involving capacity issues within our delivery infrastructure.The error message "451 Message temporarily deferred - 4.16.50" indicates that our MTAs are currently experiencing heavy, unusual traffic.You may retry sending at a later time when you see this message.
These deprioritizations were temporary but may be re-triggered if the sending IP profile continues to be poor.
Typically, deprioritizations are triggered by bad individual sender or MAIL FROM profiles.
The following link contains information on maintaining prioritized delivery when sending to Yahoo! also refer to the Help page below for more information on our recommended best practices for bulk mailers.
At the bottom of the Help page is a link to a feedback form where you can contact our Customer Care team to apply for possible whitelisting.
you are not the administrator for the mail server(s) affected, we encourage you to contact the administrator so they can address the possible issues regarding mailings from the mail server.
If you notice any further difficulties with delivering to Yahoo!Mail accounts after waiting a reasonable amount of time, please let us know by replying directly to this email.It´s interesting to note that yahoo is now censoring their message boards with regards to this issue.Yesterday I Googled for "451 Message temporarily deferred yahoo" and today, serveral of threads on Yahoo´s message boards have now been deleted.They were mostly from concerned legitimate users who were wondering why their e-mail were being delayed by hours if not days.Interesting All my mail servers are having this issue, we are trying to do retries to reconnect to yahoo every 1min and still we used to get 100K mail and now barely 20K.