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

Question

I solve this by SQL command:

ALTER USER 'mysqlUsername'@'localhost' IDENTIFIED WITH mysql_native_password BY 'mysqlUsernamePassword';

which is referenced by https://dev.mysql.com/doc/refman/8.0/en/alter-user.html

if you are creating new user

 CREATE USER 'jeffrey'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

which is referenced by https://dev.mysql.com/doc/refman/8.0/en/create-user.html

this works for me

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

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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.

ALTER USER 'mysqlUsername'@'localhost' IDENTIFIED WITH mysql_native_password BY 'mysqlUsernamePassword';

Remove quotes (') after ALTER USER and keep quote (') after mysql_native_password BY

It is working for me also.

If you're on Windows and it's not possible to use caching_sha2_password at all, you can do the following:

1. rerun the MySQL Installer
2. select "Reconfigure" next to MySQL Server (the top item)
3. click "Next" until you get to "Authentication Method"
4. change "Use Strong Password Encryption for Authentication (RECOMMENDED)" to "Use Legacy Authentication Method (Retain MySQL 5.X Compatibility)
5. click "Next"
6. enter your Root Account Password in Accounts and Roles, and click "Check"
7. click "Next"
8. keep clicking "Next" until you get to "Apply Configuration"
9. click "Execute"

The Installer will make all the configuration changes needed for you.