Error 1133 42000 can t find any matching row in the user table

To expound on Stephane’s answer.

I got this error when I tried to grant remote connections privileges of a particular database to a root user on MySQL server by running the command:

USE database_name;
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%';

This gave an error:

ERROR 1133 (42000): Can't find any matching row in the user table

Here’s how I fixed it:

First, confirm that your MySQL server allows for remote connections. Use your preferred text editor to open the MySQL server configuration file:

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf

Scroll down to the bind-address line and ensure that is either commented out or replaced with 0.0.0.0 (to allow all remote connections) or replaced with Ip-Addresses that you want remote connections from.

Once you make the necessary changes, save and exit the configuration file. Apply the changes made to the MySQL config file by restarting the MySQL service:

sudo systemctl restart mysql

Next, log into the MySQL server console on the server it was installed:

mysql -u root -p

Enter your mysql user password

Check the hosts that the user you want has access to already. In my case the user is root:

SELECT host FROM mysql.user WHERE user = "root";

This gave me this output:

+-----------+
| host      |
+-----------+
| localhost |
+-----------+

Next, I ran the command below which is similar to the previous one that was throwing errors, but notice that I added a password to it this time:

USE database_name;
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'my-password';

Note: % grants a user remote access from all hosts on a network. You can specify the Ip-Address of the individual hosts that you want to grant the user access from using the command — GRANT ALL PRIVILEGES ON *.* TO 'root'@'Ip-Address' IDENTIFIED BY 'my-password';

Afterwhich I checked the hosts that the user now has access to. In my case the user is root:

SELECT host FROM mysql.user WHERE user = "root";

This gave me this output:

+-----------+
| host      |
+-----------+
| %         |
| localhost |
+-----------+

Finally, you can try connecting to the MySQL server from another server using the command:

mysql -u username -h mysql-server-ip-address -p

Where u represents user, h represents mysql-server-ip-address and p represents password. So in my case it was:

mysql -u root -h 34.69.261.158 -p

Enter your mysql user password

You should get this output depending on your MySQL server version:

Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 4
Server version: 5.7.31 MySQL Community Server (GPL)

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> 

Resources: How to Allow Remote Connections to MySQL

That’s all.

I hope this helps