We make every effort to deliver solicited email directly to your Inbox. Sometimes, though, we can incorrectly send a message that you want to your Spam folder.
Tips to avoid having emails designated as spam:
Check your Spam folder: Periodically check your Spam folder to ensure that you do not miss a message.
- You can move a message from the Spam folder to your Inbox: Check the checkbox beside the message and select the Not Spam button.
- Using Not Spam "educates" our filtering system: By sending these examples to Yahoo for review, it will increase the effectiveness of Yahoo Mail's filtering system.
Add senders to your Contact list: Adding someone to your Contact list ensures their messages won't end up in your Spam folder.
Source: https://help.yahoo.com/kb/SLN4910.html