Why Yahoo Did not receive email

I try to send using my Outlook with hotmail account to my yahoo email. Not sure know why, the yahoo email did not received the email send from my Outlook.

At first I suspect my Outlook SMTP server port is not correct, but I try send a loop back email to own account, it was OK.

Then luckily I check the Yahoo mail setting at OPTION. There is an Advanced Option setting for "Blocked Addresses". I then try to remove the hotmail.com from "Blocked Addresses. Retry again from Outlook and finally, I manage received the email.