php mysqli_connect: authentication method unknown to the client [caching_sha2_password]

Question

I am using php mysqli_connect for login to a MySQL database (all on localhost)

Answer 1

As of PHP 7.4, this is no longer an issue. Support for caching_sha2 authentication method has been added to mysqlnd.

---

Currently, PHP mysqli extension do not support new caching_sha2 authentication feature. You have to wait until they release an update.

Check related post from MySQL developers: https://mysqlserverteam.com/upgrading-to-mysql-8-0-default-authentication-plugin-considerations/

They didn't mention PDO, maybe you should try to connect with PDO.