subscription-manager refresh shows a Traceback and "Error updating system data on the server" check: /var/log/rhsm/rhsm.log etc

gistfile1.txt

Something lik:
Traceback (most recent call last):
  File "/sbin/subscription-manager", line 9, in <module>
    load_entry_point('subscription-manager==1.24.26', 'console_scripts', 'subscription-manager')()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/scripts/subscription_manager.py", line 86, in main
    return managercli.ManagerCLI().main()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 2989, in main
    ret = CLI.main(self)
  File "/usr/lib64/python2.7/site-packages/subscription_manager/cli.py", line 183, in main
    return cmd.main()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 536, in main
    return_code = self._do_command()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 2595, in _do_command
    installed_products = products.InstalledProducts(self.cp).list(self.options.filter_string)
  File "/usr/lib64/python2.7/site-packages/rhsmlib/services/products.py", line 50, in list
    sorter = inj.require(inj.CERT_SORTER)
  File "/usr/lib64/python2.7/site-packages/subscription_manager/injection.py", line 109, in require
    return FEATURES.require(feature, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/subscription_manager/injection.py", line 83, in require
    self.providers[feature] = provider(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/subscription_manager/cert_sorter.py", line 324, in __init__
    self.update_product_manager()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/cert_sorter.py", line 354, in update_product_manager
    consumer_identity.uuid)
  File "/usr/lib64/python2.7/site-packages/subscription_manager/cache.py", line 183, in update_check
    raise Exception(_("Error updating system data on the server, see /var/log/rhsm/rhsm.log "
Exception: Error updating system data on the server, see /var/log/rhsm/rhsm.log for more details.
---
testing:
  curl -v https://subscription.rhsm.redhat.com/subscription 
shows:
..
NSS error -8179 (SEC_ERROR_UNKNOWN_ISSUER)
* Peer's Certificate issuer is not recognized.
..
as this https://access.redhat.com/solutions/68657 tries to weakly show that there is maybe something wrong with time, firewall, reboot, anything but RHEL
the correct answer, was answered by a random newbie user: 
  subscription-manager refresh --insecure
that's all