Sentinel is unable to failover in multi REDIS environment | Instances

ENVIRONMENT
REDIS-1 = 192.168.2.69 Port 8999
REDIS-2 = 192.168.2.69 Port 8999
REDIS-3 = 192.168.2.69 Port 8999

Firewall and selinux is disabled on all three REDIS machines

We have configured 3 REDIS Servers. On each server we also install sentinel. When we reboot Master, Sentinel failover and new REDIS node become Master from rest of available two REDIS machines. Till here everything is working perfect.

QUERY
Now we want to start two more REDIS instances on two different ports (port 6999 & 7999)

We started two more REDIS instances on port 6999 & 7999. Both REDIS instances have separate REDIS.conf file (redis-1.conf & redis-2.conf). These two REDIS starts thru systemctl .Below are for your reference

[root@REDIS-1 ~]# ps -ef |grep redis
redis 1769 1 0 14:32 ? 00:00:17 /usr/bin/redis-server 192.168.2.69:6999
redis 1795 1 0 14:32 ? 00:01:16 /usr/bin/redis-server 192.168.2.69:7999
redis 1811 1 0 14:33 ? 00:00:53 /usr/bin/redis-server 192.168.2.69:8999
redis 1929 1 0 15:31 ? 00:00:26 /usr/bin/redis-sentinel *:26379 [sentinel]
root 1957 1579 0 15:55 pts/0 00:00:00 redis-cli -p 26379
root 2006 1982 0 16:44 pts/1 00:00:00 grep --color=auto redis

[root@REDIS-2 ~]# ps -ef |grep redis
redis 1024 1 0 15:31 ? 00:00:08 /usr/bin/redis-server 192.168.2.71:6999
redis 1026 1 1 15:31 ? 00:00:47 /usr/bin/redis-sentinel *:26379 [sentinel]
redis 1031 1 0 15:31 ? 00:00:08 /usr/bin/redis-server 192.168.2.71:7999
redis 1034 1 0 15:31 ? 00:00:12 /usr/bin/redis-server 192.168.2.71:8999
root 1651 1626 0 16:44 pts/0 00:00:00 grep --color=auto redis

redis 1659 1 0 14:31 ? 00:00:15 /usr/bin/redis-server 192.168.2.73:6999
redis 1687 1 0 14:31 ? 00:00:15 /usr/bin/redis-server 192.168.2.73:7999
redis 1707 1 0 14:43 ? 00:00:21 /usr/bin/redis-server 192.168.2.73:8999
redis 1812 1 0 15:30 ? 00:00:28 /usr/bin/redis-sentinel *:26379 [sentinel]
root 1895 1851 0 16:44 pts/1 00:00:00 grep --color=auto redis

SENTINEL CONFIGURATION FOR NEW REDIS INSTANCES (6999 & 7999)
I did the below configuration of master on all three nodes.
sentinel monitor mymaster1 192.168.2.69 6999 2
sentinel down-after-milliseconds mymaster1 5000
sentinel failover-timeout mymaster1 60000
sentinel parallel-syncs mymaster1 1

sentinel monitor mymaster2 192.168.2.69 7999 2
sentinel down-after-milliseconds mymaster2 5000
sentinel failover-timeout mymaster2 60000
sentinel parallel-syncs mymaster2 1

[root@REDIS-3 ~]# redis-cli -p 26379
127.0.0.1:26379> info sentinel

Sentinel

sentinel_masters:3
sentinel_tilt:0
sentinel_tilt_since_seconds:-1
sentinel_running_scripts:0
sentinel_scripts_queue_length:0
sentinel_simulate_failure_flags:0
master0:name=mymaster,status=ok,address=192.168.2.69:8999,slaves=3,sentinels=4
master1:name=mymaster2,status=sdown,address=192.168.2.69:7999,slaves=0,sentinels=2
master2:name=mymaster1,status=sdown,address=192.168.2.69:6999,slaves=0,sentinels=2

ISSUE
When I reboot MASTER for port 6999 & 7999, the failover cant trigger and same MASTER keep MASTER even after a reboot
Status of other two nodes when we reboot master for port 6999 & 7999