got "ERROR 2003 (HY000): Authentication with backend failed. Session will be closed." with MySQL 8.0

I have 2 MySQL servers named esDB1 esDB2 and an isolative MaxScale server. All installed in CentOS 7 with installed information as:

[root@esDB1 ~]# cat /etc/centos-release
CentOS Linux release 7.4.1708 (Core) 
[root@esDB1 ~]#

[root@esDB1 ~]# yum list installed | grep -i mysql
mysql-commercial-client.x86_64        8.0.15-1.1.el7                   installed
mysql-commercial-common.x86_64        8.0.15-1.1.el7                   installed
mysql-commercial-libs.x86_64          8.0.15-1.1.el7                   installed
mysql-commercial-libs-compat.x86_64   8.0.15-1.1.el7                   installed
mysql-commercial-server.x86_64        8.0.15-1.1.el7                   installed
[root@esDB1 ~]#

[root@esMax1 ~]# yum list installed | grep -i maxscale
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
maxscale.x86_64                      2.4.2-1                           installed
[root@esMax1 ~]#

There are 2 users for MaxScale in DB:

mysql> SHOW GRANTS for "MaxMonitor"@"168.6.42.%";
+--------------------------------------------------------------+
| Grants for [email protected].%                             |
+--------------------------------------------------------------+
| GRANT REPLICATION CLIENT ON *.* TO `MaxMonitor`@`168.6.42.%` |
+--------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SHOW GRANTS for "MaxService"@"168.6.42.%";
+----------------------------------------------------------+
| Grants for [email protected].%                         |
+----------------------------------------------------------+
| GRANT SHOW DATABASES ON *.* TO `MaxService`@`168.6.42.%` |
| GRANT SELECT ON `mysql`.* TO `MaxService`@`168.6.42.%`   |
+----------------------------------------------------------+
2 rows in set (0.00 sec)

mysql>

The content of maxscale.cnf is:

[maxscale]
threads=auto
retain_last_statements=5
dump_last_statements=on_error


[esDB1]
type=server
address=168.6.42.111
port=3026
protocol=MariaDBBackend

[esDB2]
type=server
address=168.6.42.112
port=3026
protocol=MariaDBBackend


[MariaDB-Monitor]
type=monitor
module=mariadbmon
servers=esDB1,esDB2
user=MaxMonitor
password=MaxMonitor's password
monitor_interval=2000


[Read-Write-Service]
type=service
router=readwritesplit
servers=esDB1,esDB2
user=MaxService
password=MaxService's password


[MaxAdmin-Service]
type=service
router=cli


[Read-Write-Listener]
type=listener
service=Read-Write-Service
protocol=MariaDBClient
port=3306


[MaxAdmin-Listener]
type=listener
service=MaxAdmin-Service
protocol=maxscaled
socket=default

It can normally use the user "MaxService" directly login DB and execute SQL command.

[root@esDB1 ~]# mysql -uMaxService -p -h168.6.42.111 -P3026
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 29833
Server version: 8.0.15-commercial MySQL Enterprise Server - Commercial

Copyright (c) 2000, 2019, 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> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

mysql>

Then I start the MaxScale without any error:

[root@esMax1 ~]# systemctl start maxscale
[root@esMax1 ~]# systemctl status maxscale -l
● maxscale.service - MariaDB MaxScale Database Proxy
   Loaded: loaded (/usr/lib/systemd/system/maxscale.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2019-09-09 18:14:45 CST; 19s ago
  Process: 8378 ExecStart=/usr/bin/maxscale (code=exited, status=0/SUCCESS)
  Process: 8375 ExecStartPre=/usr/bin/install -d /var/lib/maxscale -o maxscale -g maxscale (code=exi
ted, status=0/SUCCESS)
  Process: 8372 ExecStartPre=/usr/bin/install -d /var/run/maxscale -o maxscale -g maxscale (code=exi
ted, status=0/SUCCESS)
 Main PID: 8379 (maxscale)
   CGroup: /system.slice/maxscale.service
           └─8379 /usr/bin/maxscale

Sep 09 18:14:45 esMax1 maxscale[8379]: Listening for connections at [/var/run/maxscale/maxadmin.sock]:0
Sep 09 18:14:45 esMax1 maxscale[8379]: Service 'MaxAdmin-Service' started (1/2)
Sep 09 18:14:45 esMax1 maxscale[8379]: Server 'esDB1' version: 8.0.15-commercial
Sep 09 18:14:45 esMax1 maxscale[8379]: Server 'esDB2' version: 8.0.15-commercial
Sep 09 18:14:45 esMax1 maxscale[8379]: [MariaDBAuth] [Read-Write-Service] Loaded 17 MySQL users for listener Read-Write-Listener from server esDB1.
Sep 09 18:14:45 esMax1 maxscale[8379]: Listening for connections at [::]:3306
Sep 09 18:14:45 esMax1 maxscale[8379]: Service 'Read-Write-Service' started (2/2)
Sep 09 18:14:45 esMax1 maxscale[8379]: Loaded server states from journal file: /var/lib/maxscale/MariaDB-Monitor/monitor.dat
Sep 09 18:14:45 esMax1 systemd[1]: Started MariaDB MaxScale Database Proxy.
Sep 09 18:14:45 esMax1 maxscale[8379]: [mariadbmon] Attempted to find a replacement for the current 
master server 'esDB1' because it has started replicating from another server in the cluster, but 'esDB1' is still the best master server.
[root@esMax1 ~]#

The content of maxscale.log is:

MariaDB MaxScale  /var/log/maxscale/maxscale.log  Mon Sep  9 18:14:45 2019
----------------------------------------------------------------------------
2019-09-09 18:14:45   notice : syslog logging is enabled.
2019-09-09 18:14:45   notice : maxlog logging is enabled.
2019-09-09 18:14:45   notice : Using up to 548.00MiB of memory for query classifier cache
2019-09-09 18:14:45   notice : Working directory: /var/log/maxscale
2019-09-09 18:14:45   notice : The collection of SQLite memory allocation statistics turned off.
2019-09-09 18:14:45   notice : Threading mode of SQLite set to Multi-thread.
2019-09-09 18:14:45   notice : MariaDB MaxScale 2.4.2 started (Commit: aad4148d77bf2dfbaa0042bc45abda30c101cad2)
2019-09-09 18:14:45   notice : MaxScale is running in process 8379
2019-09-09 18:14:45   notice : Configuration file: /etc/maxscale.cnf
2019-09-09 18:14:45   notice : Log directory: /var/log/maxscale
2019-09-09 18:14:45   notice : Data directory: /var/lib/maxscale
2019-09-09 18:14:45   notice : Module directory: /usr/lib64/maxscale
2019-09-09 18:14:45   notice : Service cache: /var/cache/maxscale
2019-09-09 18:14:45   notice : No query classifier specified, using default 'qc_sqlite'.
2019-09-09 18:14:45   notice : Loaded module qc_sqlite: V1.0.0 from /usr/lib64/maxscale/libqc_sqlite.so
2019-09-09 18:14:45   notice : Query classification results are cached and reused. Memory used per thread: 137.00MiB
2019-09-09 18:14:45   notice : The systemd watchdog is Enabled. Internal timeout = 30s
2019-09-09 18:14:45   notice : Loading /etc/maxscale.cnf.
2019-09-09 18:14:45   notice : /etc/maxscale.cnf.d does not exist, not reading.
2019-09-09 18:14:45   notice : Loaded module maxscaled: V2.0.0 from /usr/lib64/maxscale/libmaxscaled.so
2019-09-09 18:14:45   notice : Loaded module MariaDBClient: V1.1.0 from /usr/lib64/maxscale/libmariadbclient.so
2019-09-09 18:14:45   warning: [cli] THE 'cli' MODULE AND 'maxadmin' ARE DEPRECATED: Use 'maxctrl' instead
2019-09-09 18:14:45   notice : Loaded module cli: V1.0.0 from /usr/lib64/maxscale/libcli.so
2019-09-09 18:14:45   notice : [readwritesplit] Initializing statement-based read/write split router module.
2019-09-09 18:14:45   notice : Loaded module readwritesplit: V1.1.0 from /usr/lib64/maxscale/libreadwritesplit.so
2019-09-09 18:14:45   notice : [mariadbmon] Initialise the MariaDB Monitor module.
2019-09-09 18:14:45   notice : Loaded module mariadbmon: V1.5.0 from /usr/lib64/maxscale/libmariadbmon.so
2019-09-09 18:14:45   notice : Loaded module MariaDBBackend: V2.0.0 from /usr/lib64/maxscale/libmariadbbackend.so
2019-09-09 18:14:45   notice : Loaded module mariadbbackendauth: V1.0.0 from /usr/lib64/maxscale/libmariadbbackendauth.so
2019-09-09 18:14:45   notice : Using encrypted passwords. Encryption key: '/var/lib/maxscale/.secrets'.
2019-09-09 18:14:45   notice : Loaded module MaxAdminAuth: V2.1.0 from /usr/lib64/maxscale/libmaxadminauth.so
2019-09-09 18:14:45   notice : Loaded module mariadbauth: V1.1.0 from /usr/lib64/maxscale/libmariadbauth.so
2019-09-09 18:14:45   notice : Started REST API on [127.0.0.1]:8989
2019-09-09 18:14:45   notice : MaxScale started with 4 worker threads, each with a stack size of 8388608 bytes.
2019-09-09 18:14:45   notice : Starting a total of 2 services...
2019-09-09 18:14:45   notice : Listening for connections at [/var/run/maxscale/maxadmin.sock]:0
2019-09-09 18:14:45   notice : Service 'MaxAdmin-Service' started (1/2)
2019-09-09 18:14:45   notice : Server 'esDB1' version: 8.0.15-commercial
2019-09-09 18:14:45   notice : Server 'esDB2' version: 8.0.15-commercial
2019-09-09 18:14:45   notice : [MariaDBAuth] [Read-Write-Service] Loaded 17 MySQL users for listener Read-Write-Listener from server esDB1.
2019-09-09 18:14:45   notice : Listening for connections at [::]:3306
2019-09-09 18:14:45   notice : Service 'Read-Write-Service' started (2/2)
2019-09-09 18:14:45   notice : Loaded server states from journal file: /var/lib/maxscale/MariaDB-Monitor/monitor.dat
2019-09-09 18:14:45   warning: [mariadbmon] Attempted to find a replacement for the current master server 'esDB1' because it has started replicating from another server in the cluster, but 'esDB1' is still the best master server.

And then I can use all user's ID to login through MaxScale, but can not execute any SQL command:

[root@esMax1 ~]# mysql -uMaxService -p -h168.6.42.118
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.5-8.0.15-commercial

Copyright (c) 2000, 2019, 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>
mysql> show databases;
ERROR 2003 (HY000): Authentication with backend failed. Session will be closed.
mysql> show databases;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    2
Current database: *** NONE ***

ERROR 2003 (HY000): Authentication with backend failed. Session will be closed.
mysql>

The content of maxscale.cnf added 6 records as:

2019-09-09 18:19:35   error  : [mariadbbackend] Unable to write to backend 'esDB1' due to authentication failure. Server in state Master, Running.
2019-09-09 18:19:35   error  : [mariadbbackend] Unable to write to backend 'esDB2' due to authentication failure. Server in state Relay Master, Slave, Running.
2019-09-09 18:19:35   notice : (1) Stmt 1(1970-01-01 08:00:00): select @@version_comment limit 1
2019-09-09 18:20:04   error  : [mariadbbackend] Unable to write to backend 'esDB2' due to authentication failure. Server in state Relay Master, Slave, Running.
2019-09-09 18:20:04   notice : (2) Stmt 1(1970-01-01 08:00:00): show databases
2019-09-09 18:20:04   error  : [mariadbbackend] Unable to write to backend 'esDB1' due to authentication failure. Server in state Master, Running.

Can anyone help me to correct it?