Your Yahoo! Mail inbox does not automatically inform you every time you receive a new email. Instead, it automatically refreshes every 10 minutes and informs you then if you have received mail during that time. This means you may experience a delay between when the message arrives and when you see it. If you are expecting an important email to arrive to your Yahoo! account at a specific time, do not just open your Yahoo! inbox and wait to see it show up. Instead, refresh your Yahoo! Mail inbox regularly as you wait so you can read the email as soon as possible.
Navigate to your Yahoo! Mail inbox. This may require you to sign in with your username and password.
Wait until you believe the email in question should have appeared.
Click the curved arrow icon in the "Inbox" line in the left panel of your page. If you hover your cursor over this icon, it should say "Check for new email." Alternatively, you can simply click the "Inbox" link itself.
Look in your inbox, located in the right portion of the page, to see if the email in question has arrived yet. If not, click the "Check for new email" icon again.