If your primary emails are being sent to the spam folder, or undesired spam messages are being delivered to your Yahoo Mail account's box folder, your Yahoo Mail Spam Filter Not Working. This is most likely due to issues at Yahoo's end, or a recent change made by you. Whatever the cause, some of the following remedies will assist you in resolving the Yahoo Mail Spam filter not working issue.


How to Fix Yahoo's Spam Filtering Issue:

1- Before moving on to the next filter, each email must pass through the spam filter. Look through the spam folder if you can't find your emails in your inbox or anywhere else.

2- Make sure you haven't created an empty filter by accident (filter without rules.) The rules of the other filters will be invalidated if this filter is placed above them, and emails will be sent to the inbox.

3- Create a big number of filters with prudence. A filter sorts emails according to all of the rules; if any of the rules aren't followed, the filter isn't used. Create two separate filters if you want a filter to satisfy both of the conditions.

4- A spam filter's failure could also be due to conflicting regulations. It's not a good idea to mix positive and negative phrases in a filter.

Spam Emails: How to Avoid Them

You should also make an effort to avoid receiving spam emails in the future by remembering the following:

Replying to an unknown sender is not a good idea.
Don't give out your email address to just anyone.
It is unnecessary to respond to emails requesting that you unsubscribe from services to which you have never subscribed.
Websites that claim to help you with spam emails should be avoided because some of them are scams.


Source: https://morioh.com/p/22501ecbb4ef