System registration fails with The handshake operation timed out error

Issue

• While registering the system to the customer portal using subscription-manager register command, it fails with the below error:

  # subscription-manager register --username "" --password "xxxxxxxx" 
  Unable to reach the server at subscription rhsm.redhat.com443/subscription:_ssl.c:880: The handshake operation timed out.
  

• Registration of system using subscription-manager register command fails with below error:

  # subscription-manager register
  Registering to: subscription.rhsm.redhat.com:443/subscription
  Username: xxxxxx
  Password:
  Unable to verify server's identity: ('_ssl.c:602: The handshake operation timed out',)