Whenever I use Bing

Welcome to the Apple Support Communities.

Does it work on Safari: Browse the web using Safari on iPhone - Apple Support?

If you need help with Bing, contact the developer: How to contact an app developer - Apple Support.

Jack

See 404 checker -> https://websiteadvantage.com.au/404-Error-Handler-Checker

This is the standard message you may see when you visit a page or file that is missing. It is called an HTTP 404 Error because 404 is the HTTP status code the page should return to tell browsers or search engines that the requested URL refers to a web page or file that does not exist. 

My iPhone 12 Promax using iOS 15.4 returns the notification website not found when searching bing. When using iPad 5, running iOS 15.4, search on bing works. Something in software update for iPhone didn’t work.