Hi there @huangwuko,
Thanks for reaching out!
To combat spam and phishing, large email providers (Yahoo, Gmail, Outlook, AOL, etc.) only allow their users to send emails from their inboxes and not a third party, like MailPoet. For example, Yahoo will not accept your emails if you send a newsletter with MailPoet and your FROM email address is a Yahoo or Gmail address.
Sending emails with the MailPoet Sending Service allows you to use free addresses by default, but it will be rewritten: https://kb.mailpoet.com/article/266-authorizing-from-email-addresses#authorizing-free-email-addresses
You can read more about it here: https://kb.mailpoet.com/article/259-your-from-address-cannot-be-yahoo-com-gmail-com-outlook-com
I hope this clarifies a bit, but please let us know if you have any questions!
