Host is not allowed to connect to this MySQL server

解決方法：

[root@GYQ-Prod-Zabbix ~]# mysql -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3911752
Server version: 5.5.60-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

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

MariaDB [(none)]> GRANT ALL PRIVILEGES ON *.* TO 'zabbix'@'%' IDENTIFIED BY 'zabbix' WITH GRANT OPTION;
Query OK, 0 rows affected (0.02 sec)

MariaDB [(none)]> FLUSH   PRIVILEGES;
Query OK, 0 rows affected (0.04 sec)