Iphone 8 yahoo mail problems

Greetings, John.H.Hall.
Thank you for trying those steps and getting back to us. I have a few questions I'd like to ask you and another step to try.

1. Which iOS is your iPhone 8 currently on?
2. When did this issue begin?
3. Do you have other email accounts and are they working properly?

How to check the storage on your iPhone, iPad, and iPod touch -- I'd like for you to offload the Mail application. Offloading will remove the application, but leave your data in place. Go to Settings > General > iPhone Storage, scroll to the Mail application and tap "Offload App". Once the application has been removed, reinstall it again and test.

Get back to me when you can.

Enjoy your day!

Hey there, John.H.Hall.

After reviewing your post, it appears that the email from your Yahoo account isn't automatically appearing in the Mail application on your iPhone 8. Yahoo has addressed this issue and I'm happy to share it with you.

Set up or remove a Yahoo Mail account in the iOS Mail app -- If you used the automated setup for your account, remove the account and follow the steps under "Manually add a Yahoo Mail account using IMAP settings" and "Update fetch settings to get timely notifications". You can also refer to "Remove a Yahoo Mail account" for help with removing the account.

Let me know if you have any questions or issues.

Take care!