Cant open safari (Error 400)

Hi Irek7700,

Welcome to the Apple Community.

Wondering

whether the error happens on all websites, or just the one in your screenshot.

and

if you are sure that you have entered the correct address ...

eg: you might want to try: https://myaccount.google.com

also,

whether you have installed the iOS updates that came after iOS 15

Apple have this article online:

Update to the latest version of Safari

https://support.apple.com/en-us/HT204416

If you still need help:

There is a "Get Support" link to Apple at top right on this discussion page.

or

Apple phone numbers around the world

https://support.apple.com/en-us/HT201232

All the best :-)