RHOCP4 disconnected Image mirroring fails with connection refused

Issue

• While trying to perform image mirror using oc-mirror, the process fails with the following error :-

  Checking push permissions for mirror.example.com
  error: error checking push permissions for mirror.example.com: creating push check transport for mirror.example.com failed: Get "https://mirror.example.com/v2/": dial tcp <system_IP>:443: connect: connection refused
  

• The required ports are already opened on the registry server, but still the connectivity issue persists.

  $ netstat -tnlp
  Active Internet connections (only servers)
  Proto   Recv-Q    Send-Q      Local Address      Foreign Address      State       PID/Program name
  tcp        0        0         127.0.0.1:631       0.0.0.0:*           LISTEN        1153/cupsd
  tcp        0        0         0.0.0.0:22          0.0.0.0:*           LISTEN        1352/sshd: /usr/sbi
  tcp        0        0         :::22               :::*                LISTEN        1352/sshd: /usr/sbi
  tcp6       0        0         :::80               :::*                LISTEN        44825/httpd
  tcp6       0        0         ::1:631             :::*                LISTEN        1153/cupsd
  
  $ ping <mirror_registry_URL>
  64 bytes from <mirror_registry_URL>: icmp_seq=1 ttl=64 time=0.072 ms
  64 bytes from <mirror_registry_URL>: icmp_seq=2 ttl=64 time=0.059 ms
  64 bytes from <mirror_registry_URL>: icmp_seq=3 ttl=64 time=0.054 ms
  64 bytes from <mirror_registry_URL>: icmp_seq=4 ttl=64 time=0.199 ms