If email addressees are not receiving messages that have been sent via automated services such as mailing lists or groups, or you are receiving returned email stating that your messages have been rejected for policy reasons, you should use a business email address associated to your domain name as the sending address. Due to recent changes to protect our users, sending from your “@yahoo.com” address may no longer work.
Yahoo recently changed our DMARC policy to proactively protect our users from increasing email forgery spam. This is an important step to secure our users’ email identities from being used by unauthorized senders.
For more information on these changes, please see this help page.