Your account is temporary blocked for sending emails within a 24 hours period. But you can still receive and view your mails.
Yahoo Mail detected an unusual activity on your account. Sending too many e-mail in a large group may have trigger the suspension of your account. Yahoo Mail protects its users from spams. Activity like sending e-mail on a large scale suspected this as spam.
If you are planning on sending message in a group, It is better if you batch it by 100/group. It is better also if there is a time interval per sending.
Your account will work again after 24 hours. You just have to wait.
However, if your account is sending failure after 24 hours, It is advisable to report this issue to the Customer Care of Yahoo Mail. How? click this linkhttp://help.yahoo.com/l/us/yahoo/mail/postmaster/abuse_smtp.html
Fill up completely the Yahoo Help Form.
And click Submit button. In a few time your account will be able to send messages again.
Let me know if your sending is unblock.
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