After updating (through -apt update and apt upgrade) access to the installation of MantisBT has become useless. The databases and users are intact. Access to the server (VPS) through SSH is available and intact.
The connection to the database has failed. The error returned by the database was # 2054: The server requested authentication method unknown to the client Use the «Back» button in your web browser to return to the previous page. There you can correct the problems that have been identified in this error notification or select another action. You can also click on an option in the menu bar to go directly to a new section.
Error in phpmyadmin:
2054 - The server requested authentication method unknown to the client
mysqli_real_connect(): The server requested authentication method unknown to the client [caching_sha2_password]
mysqli_real_connect(): (HY000/2054): The server requested authentication method unknown to the client
Ubuntu 18.04.2 LTS
Release: 18.04
PHP 7.2.15-0ubuntu0.18.04.1 (cli) (built: Feb 8 2019 14:54:22) ( NTS )
mysql Ver 8.0.15 for Linux on x86_64 (MySQL Community Server - GPL)
Server version: Apache/2.4.29 (Ubuntu)
I modified the MySQL configuration:
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'rootpassword'
but I get the following error:
ERROR 3009 (HY000): Column count of mysql.user is wrong. Expected 51, found 50. Created with MySQL 80013, now running 80015. Please use mysql_upgrade to fix this error.
When trying to update the MySQL instance:
mysql_upgrade: Got error: 1045: Access denied for user 'root'@'localhost' (using password: NO) while connecting to the MySQL server
Upgrade process encountered error and will not continue.
Log in to MySQL console with root user:
mysql -u root -p<password>
Run the following code:
ALTER USER root IDENTIFIED WITH mysql_native_password BY 'NEW PASSWORD';
You must change 'NEW PASSWORD' to your new password and then try to login.
Hope this will help.