Point of departure

Because the bridge project needs to use MySQL database, thinking that the MySQL of my laboratory server has been installed, I installed Navicat to prepare for remote connection, and connected through the shell to find that the operation was normal

mysql -u root -p

But an error occurred when using Navicat to connect, and the connection was refused, so I thought that MySQL might not allow remote login

Enable remote IP login permission

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

Add bind-address = 127.0.0.1before#

lc-messages-dir = /usr/share/mysql
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
# bind-address          = 127.0.0.1

Then restart MySQL

/etc/init.d/mysql restart

Add user

After opening the remote login, a new error occurred: ...is not allowed to connect to this MySql server
So log in to MySQL through the shell, and execute the following commands in turn

use mysql;update user set host=’%’ where user=’root’;

Then the remote connection is successful