execute masterha_master_switch, Got Error: user account was not correctly passed.

[hqlswc]

[HELP] When I execute masterha_master_switch, always got error

[root@slave-248212 ~]# masterha_master_switch --conf=/etc/masterha/app1.cnf --master_state=alive --new_master_host=10.5.248.211 --orig_master_is_new_slave

Sun Jun  2 22:30:05 2019 - [info] MHA::MasterRotate version 0.58.
Sun Jun  2 22:30:05 2019 - [info] Starting online master switch..
Sun Jun  2 22:30:05 2019 - [info]
Sun Jun  2 22:30:05 2019 - [info] * Phase 1: Configuration Check Phase..
Sun Jun  2 22:30:05 2019 - [info]
Sun Jun  2 22:30:05 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Jun  2 22:30:05 2019 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Jun  2 22:30:05 2019 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Jun  2 22:30:06 2019 - [info] GTID failover mode = 0
Sun Jun  2 22:30:06 2019 - [info] Current Alive Master: 10.5.248.212(10.5.248.212:3306)
Sun Jun  2 22:30:06 2019 - [info] Alive Slaves:
Sun Jun  2 22:30:06 2019 - [info]   10.5.248.211(10.5.248.211:3306)  Version=5.7.22-log (oldest major version between slaves) log-bin:enabled
Sun Jun  2 22:30:06 2019 - [info]     Replicating from 10.5.248.212(10.5.248.212:3306)
Sun Jun  2 22:30:06 2019 - [info]     Primary candidate for the new Master (candidate_master is set)

It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on 10.5.248.212(10.5.248.212:3306)? (YES/no): yes
Sun Jun  2 22:30:09 2019 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time..
Sun Jun  2 22:30:09 2019 - [info]  ok.
Sun Jun  2 22:30:09 2019 - [info] Checking MHA is not monitoring or doing failover..
Sun Jun  2 22:30:09 2019 - [info] Checking replication health on 10.5.248.211..
Sun Jun  2 22:30:09 2019 - [info]  ok.
Sun Jun  2 22:30:09 2019 - [info] 10.5.248.211 can be new master.
Sun Jun  2 22:30:09 2019 - [info]
From:
10.5.248.212(10.5.248.212:3306) (current master)
 +--10.5.248.211(10.5.248.211:3306)

To:
10.5.248.211(10.5.248.211:3306) (new master)
 +--10.5.248.212(10.5.248.212:3306)

Starting master switch from 10.5.248.212(10.5.248.212:3306) to 10.5.248.211(10.5.248.211:3306)? (yes/NO): yes
Sun Jun  2 22:30:11 2019 - [info] Checking whether 10.5.248.211(10.5.248.211:3306) is ok for the new master..
Sun Jun  2 22:30:11 2019 - [info]  ok.
Sun Jun  2 22:30:11 2019 - [info] 10.5.248.212(10.5.248.212:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host.
Sun Jun  2 22:30:11 2019 - [info] 10.5.248.212(10.5.248.212:3306): Resetting slave pointing to the dummy host.
Sun Jun  2 22:30:11 2019 - [info] ** Phase 1: Configuration Check Phase completed.
Sun Jun  2 22:30:11 2019 - [info]
Sun Jun  2 22:30:11 2019 - [info] * Phase 2: Rejecting updates Phase..
Sun Jun  2 22:30:11 2019 - [info]
Sun Jun  2 22:30:11 2019 - [info] Executing master ip online change script to disable write on the current master:
Sun Jun  2 22:30:11 2019 - [info]   /etc/masterha/master_ip_online_change --command=stop --orig_master_host=10.5.248.212 --orig_master_ip=10.5.248.212 --orig_master_port=3306 --orig_master_user='root' --new_master_host=10.5.248.211 --new_master_ip=10.5.248.211 --new_master_port=3306 --new_master_user='root' --orig_master_ssh_user=root --new_master_ssh_user=root   --orig_master_is_new_slave --orig_master_password=xxx --new_master_password=xxx
orig master ssh user: root
new master ssh user: root
Got Error: user account was not correctly passed.

Sun Jun  2 22:30:11 2019 - [error][/usr/local/share/perl5/MHA/ManagerUtil.pm, ln177] Got ERROR:  at /usr/local/bin/masterha_master_switch line 53.

I'm sure the SSH configuration and account info absolute correct
[root@slave-248212 ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf

Sun Jun  2 22:50:51 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Jun  2 22:50:51 2019 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Sun Jun  2 22:50:51 2019 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Sun Jun  2 22:50:51 2019 - [info] Starting SSH connection tests..
Sun Jun  2 22:50:51 2019 - [debug]
Sun Jun  2 22:50:51 2019 - [debug]  Connecting via SSH from root@10.5.248.211(10.5.248.211:22) to root@10.5.248.212(10.5.248.212:22)..
Sun Jun  2 22:50:51 2019 - [debug]   ok.
Sun Jun  2 22:50:52 2019 - [debug]
Sun Jun  2 22:50:51 2019 - [debug]  Connecting via SSH from root@10.5.248.212(10.5.248.212:22) to root@10.5.248.211(10.5.248.211:22)..
Sun Jun  2 22:50:51 2019 - [debug]   ok.
Sun Jun  2 22:50:52 2019 - [info] All SSH connection tests passed successfully.

This is MHA configure
[root@slave-248212 ~]# cat /etc/masterha/app1.cnf

[server default]
# MYSQL USER
user=root
password=xxx
# SSH USER
ssh_user=root
# BINLOG
master_binlog_dir=/data/mysql3306
# MHA WORKDIR
manager_workdir=/var/log/masterha/app1
manager_log=/var/log/masterha/app1/app1.log
remote_workdir=/var/log/masterha/app1
# SWITCH
master_ip_failover_script=/etc/masterha/master_ip_failover
master_ip_online_change_script=/etc/masterha/master_ip_online_change
# REPLICATION USER
repl_user=repl
repl_password=xxx
# PING
ping_interval=1

[server1]
hostname=10.5.248.211
candidate_master=1
check_repl_delay=0

[server2]
hostname=10.5.248.212
candidate_master=1
check_repl_delay=0

[hqlswc]

modify master_ip_online_change, the problem has been sloved.

but there are two question:

1. why the ssh_user must be no root user?
2. $orig_master_password ne "msandbox" , what's the meaning of "msandbox"?