Make sure everything is up to date. Yahoo Mail updates behind the scenes, so you don't necessarily know when a new version is up. Some changes may mean that the platform won't work on the current version of the browser or app you have installed, so you should check for updates and see if that helps the issue. If yahoo mail not receiving some emails, then contact Yahoo. If none of these solutions work, you should reach out to Yahoo support so a representative can walk you through additional troubleshooting steps.