If you can not connect MediaWiki with your MySQL password and user name, do the following steps.
sudo /etc/init.d/mysql stop
Once MySQL has stopped, run:
sudo mysqld_safe --skip-grant-tables &
When MariaDB is loaded, run the following command but replace username and password with one of your choosing.
GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost' IDENTIFIED BY 'password';
Or try to reset the root password:
sudo /etc/init.d/mysql stop sudo mysqld_safe --skip-grant-tables & sudo mysql -uroot
when MariaDB is loaded, run the following commands but replace newpassword with the one you want.
use mysql;
press enter, then:
update user set password=PASSWORD("newpassword") where User='root';
press enter, then:
flush privileges;
press enter, then:
quit
press enter
Now stop and restart MySQL
sudo /etc/init.d/mysql stop sudo /etc/init.d/mysql start
Try logging into MySQL
sudo mysql -u root -p
At this point you may have to add a new user if the root password will not work.
After logging into MySQL, like before, run this command:
GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost' IDENTIFIED BY 'password';