Why is my email not updating on my iPhone?

Yahoo! and Gmail use App Specific Passwords.

Check here for Yahoo -> https://help.yahoo.com/kb/SLN27791.html

Check here for Gmail -> https://support.google.com/mail/answer/185833?hl=en-GB 

You need a good Service & Wi-Fi.

If they are On, turn Off Hotspot & VPN.

Then read again -> Related Article -> If you can't receive email on your iPhone, iPad, or iPod touch

My Yahoo! and Gmail are not automatically updating on my iPhone 13. I have to open the Mail app in order for the my mail to update and receive any incoming mail. This has been an issue for almost a week. I have excellent service and WiFi. And, I tried removing my Yahoo! mail and reinstalling it - that did not fix the issue. This seems to be an issue with other people's iPhones I have spoken with. Is this an issue Apple is already looking into?

I am not having an issue receiving e-mails from Yahoo! and Gmail. The issue is I have to open the Mail app for it to update and receive new emails. This was not an issue a week ago. Both email platforms were getting emails to my Maill app on a regular basis - I was notified whenever new emails came through without me having to open the app. I have been using both paltfomrs for many years - this is a new issue.