如果Navicat 报错:1130-host ... is not allowed to connect to this MySql server，则用以下方法解决：

mysql -u root -p    //输入账号或密码

mysql>use mysql;

mysql>update user set host = '%' where user = 'root'  and host='localhost';

mysql>select host, user from user;

如如再次连接出现1251错误，则用以下方法解决：

mysql> ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'xsg123456
';
Query OK, 0 rows affected (0.17 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)